[llvm] [libcxx] [ci] Make the CI find the right version of Clang-cl (PR #161736)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

I filed https://github.com/llvm/llvm-project/issues/161808 for the new issue in the Clang headers.

https://github.com/llvm/llvm-project/pull/161736