[libunwind] [libc++][lit] Allow overriding the executor for tests (PR #66545)

[Alexander Richardson via cfe-commits]

arichardson wrote:

> @arichardson
> 
> here is a problem with your changes when building the libraries on the windows cross toolchain builders
> 
> * https://lab.llvm.org/buildbot/#/builders/60/builds/14086
> * https://lab.llvm.org/buildbot/#/builders/119/builds/15283
> 
> https://lab.llvm.org/buildbot/#/builders/60/builds/14086/steps/12/logs/stdio
> 
> ```
> llvm-lit.py: C:\buildbot\as-builder-1\x-armv7l\llvm-project\llvm\utils\lit\lit\TestingConfig.py:151: fatal: unable to parse config file 'C:/buildbot/as-builder-1/x-armv7l/build/runtimes/runtimes-armv7-unknown-linux-gnueabihf-bins/libunwind/test/cmake-bridge.cfg', traceback: Traceback (most recent call last):
>   File "C:\buildbot\as-builder-1\x-armv7l\llvm-project\llvm\utils\lit\lit\TestingConfig.py", line 139, in load_from_path
>     exec(compile(data, path, "exec"), cfg_globals, None)
>   File "C:/buildbot/as-builder-1/x-armv7l/build/runtimes/runtimes-armv7-unknown-linux-gnueabihf-bins/libunwind/test/cmake-bridge.cfg", line 7
>     config. 'executor="C:/Python310/python.exe" "C:/buildbot/as-builder-1/x-armv7l/llvm-project/libcxx/utils/ssh.py" --host = "ubuntu at jetson6.lab.llvm.org'"
>                                                                                                                                                            ^
> SyntaxError: unterminated string literal (detected at line 7)
> ```
> 
> would you take care of it?
> 
> UPDATE: Just let me know if you will need to check you changes before commit. I will test them on the builder locally.

Sorry about that! It looks like the cmake file quoting needs to be updated. Alternatively I could revert the part of this change that deprecates the executor variable. I will take a look at this first thing tomorrow morning. If it's more urgent, feel free to revert the change.

https://github.com/llvm/llvm-project/pull/66545