[clang] [clang][deps] Stop lexing if hit a failure while loading a PCH/module in a submodule. (PR #146976)

[Volodymyr Sapsai via cfe-commits]

vsapsai wrote:

> Seems like this should have a release note?

What is the bar for a change to be release noted? This change is pretty much "make clang-scan-deps less likely to crash" and personally I don't think it deserves a release note.

https://github.com/llvm/llvm-project/pull/146976