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

[Aaron Ballman via cfe-commits]

AaronBallman 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.
> 
> If a user can see different behavior after the change then we should document that. I did not notice this was a follow-up change but the previous change also did not have a release note.
> 
> If this is completely an internal change and only llvm folks will see a different, then sure but at least it looks like from the test that this will cause different behavior for users.
> 
> CC @AaronBallman

We've got some [docs](https://llvm.org/docs/DeveloperPolicy.html#release-notes) on this, but that's basically the bar. Almost every PR should have a release note unless the PR is NFC or modifying something that hasn't yet been released (and doesn't require the existing release note to be updated). Fixing a crashing bug is something we should tell users about; it's good to recognize when we're improving quality as opposed to just adding new functionality.

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