v2.1: Fixes clean_old_storages_with_reclaims tests (backport of #4147)

[mergify]

Problem

The two accounts-db clean_old_storages_with_reclaims tests incorrectly set up the dirty stores/uncleaned pubkeys to test out the desired clean situations. This is because uncleaned_roots is used, but this struct is not responsible for deciding which slots to load as clean candidates.

Summary of Changes

Fixes the tests to not use uncleaned_roots.

Justification to Backport

We added (and backported) code and tests for fixing some accounts-db clean issues. There seems to still be an accounts-db clean issue that RPC nodes have been hitting. If we find, fix, and backport that issue, I'd like to have the current clean tests be correct. This backport PR fixes those tests.

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This is an automatic backport of pull request #4147 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 4eabeed has failed:

On branch mergify/bp/v2.1/pr-4147
Your branch is up to date with 'origin/v2.1'.

You are currently cherry-picking commit 4eabeedaa.
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Unmerged paths:
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	deleted by us:   accounts-db/src/accounts_db/tests.rs

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[HaoranYi]

lgtm.