[clang] [Modules] No transitive source location change (PR #86912)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

> I have a few minor comments on the patch. I want to do some additional perf testing on module scanning perf because I'm a bit concerned about the cost of `ASTWriter::getRawSourceLocationEncoding`.

What's the perf results about scanning?

https://github.com/llvm/llvm-project/pull/86912