[clang] [Clang] add emit -Wignored-base-class-qualifiers diagnostic for cv-qualified base classes (PR #132116)

[Lyle Dean via cfe-commits]

lyledean1 wrote:

CI seems to be failing with the message `no such option: --break-system-packages` from `pip` for `[buildkite/github-pull-requests/linux-linux-x64](https://buildkite.com/llvm-project/github-pull-requests/builds/164119#0195f387-c1b7-4bc5-8fb8-cc8049f19033)` and [buildkite/github-pull-requests](https://buildkite.com/llvm-project/github-pull-requests/builds/164119)

But haven't changed anything around this? 

https://github.com/llvm/llvm-project/pull/132116