[clang] [NFC] [ASTMatchers] Share code of `forEachArgumentWithParamType` with UnsafeBufferUsage (PR #132387)

[Ilya Biryukov via cfe-commits]

ilya-biryukov wrote:

> I'm currently dealing with downstream conflicts with your previous patch. Please do not merge this PR this week, otherwise it may slow down our CI. Thanks!

Sure! There is no urgency in landing this.
Please let me know when it'd be a good time to land this.


@AaronBallman it'd be nice to get this reviewed anyway to make sure this change makes sense from the matchers side.

https://github.com/llvm/llvm-project/pull/132387