[clang-query] Parallel runner for clang-query

[capitan-davide]

Similarly to run-clang-tidy.py, should we have a parallel runner for clang-query as well? For big searches in big codebases.

[llvmbot]

@llvm/issue-subscribers-clang-query

Author: Davide Cunial (capitan-davide)

Similarly to [run-clang-tidy.py](https://github.com/llvm/llvm-project/blob/main/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py), should we have a parallel runner for `clang-query` as well? For big searches in big codebases.