[clang] [compiler-rt] [llvm] [UBSan] Add -fsanitize=uninitialized-read check (ISO C 6.3.2.1p2) (PR #207529)

[Fangrui Song via cfe-commits]

MaskRay wrote:

This is pretty typical AI slop. I would encourage a sanitizer maintainer to take over of this patch, instead of wasting time on reviews.

https://github.com/llvm/llvm-project/pull/207529