[clang-tools-extra] Add flag to specify an alternative to std::forward (PR #138755)

[Congcong Cai via cfe-commits]

https://github.com/HerrCai0907 approved this pull request.

LGTM.
It looks similar as https://github.com/llvm/llvm-project/pull/138757. could you add a test for both PR.

https://github.com/llvm/llvm-project/pull/138755