[llvm] [SPIR-V] Fix DebugScope resolving DILexicalBlockFile to DebugCompilationUnit (PR #228259)

[Jinsong Ji via llvm-commits]

jsji wrote:

Thanks for the review! You're right that the SPIR-V is still legal — updated the commit message to say "incorrect debug scope resolution" instead of "malformed SPIR-V". Also fixed the comments to mention DebugLexicalBlockDiscriminator and changed `while` to `if`.

https://github.com/llvm/llvm-project/pull/228259