Cleanup: misc.py: add support signal_value_as_string{,_not}_equal(a,b)

[dlmiles]

misc.py: add support signal_value_as_string{,_not}_equal(a,b)

This seems like a common usage pattern in test cases.

LOW risk changes

This is a FAST-FORWARD on top of 20of20, merge with rebase.

THIS IS COMMIT ID f705aa3 THAT HAS BEEN TESTED BELOW WITH RECENT SpinalHDL/dev

20of20 (dlmiles/SpinalHDL-CocotbLib.git#f705aa3e8) test results below:

[info] Run completed in 11 minutes, 47 seconds.
[info] Total number of tests run: 956
[info] Suites: completed 145, aborted 0
[info] Tests: succeeded 956, failed 0, canceled 0, ignored 0, pending 0
[info] All tests passed.
[success] Total time: 750 s (12:30), completed May 17, 2023, 10:58:22 AM
EXIT=0

# git log -n3 --oneline --format="%h %d %cd %s"
b092475ca  (HEAD -> dev) Wed May 17 10:37:37 2023 +0000 .gitmodules: ADDED https://github.com/dlmiles/SpinalHDL-CocotbLib.git#dlm-cleanup#f705aa3e8c
e26329834  Wed May 17 10:36:57 2023 +0000 .gitmodules: REMOVE
d15b083a7  (github/dev) Tue May 16 13:23:25 2023 +0100 Add PhaseRandomizedMem

# git diff HEAD~2..HEAD
diff --git a/.gitmodules b/.gitmodules
index 0bb3f0921..073f2a372 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,4 @@
 [submodule "tester/src/test/python/cocotblib"]
        path = tester/src/test/python/cocotblib
-       url = https://github.com/SpinalHDL/CocotbLib.git
+       url = https://github.com/dlmiles/SpinalHDL-CocotbLib.git
+       branch = dlm-cleanup
diff --git a/tester/src/test/python/cocotblib b/tester/src/test/python/cocotblib
index a98830423..f705aa3e8 160000
--- a/tester/src/test/python/cocotblib
+++ b/tester/src/test/python/cocotblib
@@ -1 +1 @@
-Subproject commit a98830423924fc89bfebae84cb802fc90d352602
+Subproject commit f705aa3e8c9ed4e9290f50e6051ef353a5121113