[clang] [Sanitize] fix crash in -fsanitize-annotate-debug-info (PR #149237)

[Shafik Yaghmour via cfe-commits]

https://github.com/shafik commented:

Next time can you add more details to the summary, these are especially helpful for downstream folks but also for reviewers. Something along the lines of "Perform a null check in SanitizerAnnotateDebugInfo for the result of getCurrentDebugLocation".

https://github.com/llvm/llvm-project/pull/149237