[clang-tidy] Fix crash when diagnostic is emit with invalid location

Fix crash when diagnostic is emit with invalid location,
but with attached valid ranges. Diagnostic can contain
invalid location, but SourceManager attached to it still
can be valid, use it in such case or fallback to known
SourceManager.

Fixes: #64602

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D157649