[OpenMP][libomp] Remove Perl in favor of Python

[jpeyton52]

• Removes all Perl scripts and modules
• Adds Python3 scripts which mimic the behavior of the Perl scripts
• Removes Perl from CMake; Adds Python3 requirement to CMake
• The check-instruction-set.pl script is Knights Corner specific. The script is removed and not replicated with a corresponding Python3 script.

Relevant Discourse:
https://discourse.llvm.org/t/error-compiling-clang-with-offloading-support/79223/4

Fixes: #62289

[github-actions]

✅ With the latest revision this PR passed the Python code formatter.

[shiltian]

Can you also add in the document that Python 3 is required to build libomp? Also, does it make sense not to enable i18 by default such that Python 3 would not become required dependence?

[jpeyton52]

Where in the documentation do we want to note the requirement? Please note that Python3 is REQUIRED for LLVM development in general (https://github.com/llvm/llvm-project/blob/main/llvm/CMakeLists.txt#L915) and is not just there to enable lit testing.

We still need the scripts to generate the default English messages (no real i18n enabled) in kmp_i18n_id.inc and kmp_i18n_default.inc on all platforms and the *.def files on Windows.

[shiltian]

We had a complaint in the past about that we didn't mention we need perl in the document (openmp/README.rst), but since now we are moving to Python and it is required by LLVM project, I guess it will be fine.

[shiltian]

LGTM

[jhuber6]

Thanks so much for addressing this.