Update ion tests and add null & nan comparisions

[jpschorr]

This PR builds on #540 & #542 and adds the ability for comparisons to treat NULLs as equal and/or NaNs as equal.
NaN-equality is mostly of interest for testing against expected examplars.
NULL-equality is used likewise, but also important for compliance with PartiQL's specified semantics for eqg.

There are still todos and some additional test failures that will be addressed by future PRs that add functionality.

To see the ultimate end-point of this integration, refer to #536 and note the test coverage and conformance test results.

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Attention: Patch coverage is 37.85714% with 87 lines in your changes missing coverage. Please review.

Project coverage is 80.12%. Comparing base (f684ea9) to head (7b7ac33).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
extension/partiql-extension-ion/src/boxed_ion.rs	35.83%	77 Missing ⚠️
partiql-value/src/boxed_variant.rs	0.00%	6 Missing ⚠️
partiql-value/src/variant.rs	66.66%	4 Missing ⚠️

❌ Your patch status has failed because the patch coverage (37.85%) is below the target coverage (85.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #543      +/-   ##
==========================================
+ Coverage   80.08%   80.12%   +0.03%     
==========================================
  Files          95       95              
  Lines       20465    20581     +116     
  Branches    20465    20581     +116     
==========================================
+ Hits        16390    16490     +100     
- Misses       3640     3648       +8     
- Partials      435      443       +8     

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[github-actions]

Conformance comparison report

	Base (f684ea9)	9025898	+/-
% Passing	86.31%	87.14%	0.82%
✅ Passing	5549	5602	53
❌ Failing	880	827	-53
🔶 Ignored	0	0	0
Total Tests	6429	6429	0

Number passing in both: 5549

Number failing in both: 827

Number passing in Base (f684ea9) but now fail: 0

Number failing in Base (f684ea9) but now pass: 53

The following test(s) were previously failing but now pass. Before merging, confirm they are intended to pass:

Click here to see

• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_lists_items_should_be_ordered_by_data_types_desc_nulls_first_as_default_for_desc
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_structs_should_be_ordered_by_data_types_asc_nulls_last_as_default_for_asc
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_int_result_null_int
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_symbol_result_null_symbol
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_clob_result_null_clob
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_lob_types_follow_their_lexicographical_ordering_by_octet_asc
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_nan_before_inf_then_numeric_values_then_inf_asc
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_null_result_null
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_list_result_null_list
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_text_types_compared_by_lexicographical_ordering_of_unicode_scalar_asc
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_blob_result_null_blob
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_bool_result_null_bool
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_text_types_compared_by_lexicographical_ordering_of_unicode_scalar_desc
• partiql_tests::eval::ion::query::query::select::projection::project_various_container_types::strict_project_of_sexp
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_bool_result_null_bool
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_lob_types_should_ordered_desc
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_decimal_result_null_decimal
• partiql_tests::eval::ion::primitives::primitives::operators::nary_operators::nary::strict_equal_list_different_types_true
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_text_types_compared_by_lexicographical_ordering_of_unicode_scalar_desc
• partiql_tests::eval::ion::primitives::primitives::symbol::empty_symbol::permissive_empty_symbol_in_table
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_decimal_result_null_decimal
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_structs_should_be_ordered_by_data_types_desc_nulls_first_as_default_for_desc
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_int_result_null_int
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_lob_types_follow_their_lexicographical_ordering_by_octet_asc
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_text_types_compared_by_lexicographical_ordering_of_unicode_scalar_asc
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_nan_before_inf_then_numeric_values_then_inf_asc
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_struct_result_null_struct
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_null_result_null
• partiql_tests::eval::ion::primitives::primitives::operators::nary_operators::nary::strict_equal_bag_different_types_different_order_true
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_string_result_null_string
• partiql_tests::eval::ion::primitives::primitives::operators::nary_operators::nary::permissive_equal_bag_different_types_different_order_true
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_lists_items_should_be_ordered_by_data_types_asc_nulls_last_as_default_for_asc
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_inf_before_numeric_values_then_inf_then_nan_desc
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_structs_should_be_ordered_by_data_types_asc_nulls_last_as_default_for_asc
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_struct_result_null_struct
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_list_result_null_list
• partiql_tests::eval::ion::query::query::select::projection::project_various_container_types::permissive_project_of_sexp
• partiql_tests::eval::ion::primitives::primitives::operators::nary_operators::nary::strict_equal_bag_different_types_with_null_missing_different_order_true
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_structs_should_be_ordered_by_data_types_desc_nulls_first_as_default_for_desc
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_clob_result_null_clob
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_symbol_result_null_symbol
• partiql_tests::eval::ion::primitives::primitives::null::null::strict_null_pass_through_sql_null_sexp_result_null_sexp
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_lists_items_should_be_ordered_by_data_types_desc_nulls_first_as_default_for_desc
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_sexp_result_null_sexp
• partiql_tests::eval::ion::primitives::primitives::operators::nary_operators::nary::permissive_equal_bag_different_types_with_null_missing_different_order_true
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_blob_result_null_blob
• partiql_tests::eval::ion::query::query::select::from_clause::various_types_in_from_clause::strict_range_over_sexp
• partiql_tests::eval::ion::primitives::primitives::null::null::permissive_null_pass_through_sql_null_string_result_null_string
• partiql_tests::eval::ion::query::query::order_by::edge_cases::permissive_lob_types_should_ordered_desc
• partiql_tests::eval::ion::query::query::select::from_clause::various_types_in_from_clause::permissive_range_over_sexp
• partiql_tests::eval::ion::primitives::primitives::operators::nary_operators::nary::permissive_equal_list_different_types_true
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_inf_before_numeric_values_then_inf_then_nan_desc
• partiql_tests::eval::ion::query::query::order_by::edge_cases::strict_lists_items_should_be_ordered_by_data_types_asc_nulls_last_as_default_for_asc

[jpschorr]

There are some lingering warnings of the form ...is more private than the item...

They are fixed in #544 : for example: https://github.com/partiql/partiql-lang-rust/pull/544/files#diff-b95d0de35899342f30d2531c8cd3728a958d846d163f0c154c204f7aeb8979ceL112