Cleanup 17of20: ClockDomain.py: compute self.frequency for __str__ (MED)

[dlmiles]

MEDIUM risk changes (guess at original design intention)

This is a FAST-FORWARD on top of 16of20, merge with rebase.

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

# 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