[compiler-rt] [llvm] [lit] [compiler-rt] Add llvm-lit global command cache to speed up test config (PR #195888)

[via llvm-commits]

dyung wrote:

This change seems to be causing bot failures, can you take a look?

https://lab.llvm.org/buildbot/#/builders/190/builds/42144
```
# RUN: at line 1
"/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/bin/python3.9" /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/utils/lit/tests/unit/Util.py
# executed command: /Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/bin/python3.9 /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/utils/lit/tests/unit/Util.py
# .---command stderr------------
# | .lit: /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/llvm/utils/lit/lit/util.py:464: fatal: Failed to run date -Ins
# | rc:1
# | stdout:b''
# | e.stderrb"date: invalid argument 'ns' for -I\n"
# | E.
```

https://lab.llvm.org/buildbot/#/builders/181/builds/42869
https://lab.llvm.org/buildbot/#/builders/174/builds/35443
```
Traceback (most recent call last):
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/./bin/llvm-lit", line 50, in <module>
    import lit.util
  File "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/lit/lit/util.py", line 446, in <module>
    @functools.cache
AttributeError: module 'functools' has no attribute 'cache'
```

https://github.com/llvm/llvm-project/pull/195888