[llvm] [Github][Bazel] Add Workflow to Run Bazel Build (PR #165071)

[Jordan Rupprecht via llvm-commits]

https://github.com/rupprecht approved this pull request.

LGTM. I don't have enough background to know if the other comments are blocking, but at least to me, seems like an improvement to have this vs having nothing. Thanks for adding this!

https://github.com/llvm/llvm-project/pull/165071