[clang] [Clang] Fix assertion "unsigned range includes negative?" in AnalyzeComparison during Sema of vector comparison with mismatched signed/unsigned types and __builtin_convertvector (PR #182627)

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keinflue wrote:

@YutongZhuu I don't know the code well enough to give a useful review.

https://github.com/llvm/llvm-project/pull/182627