[llvm] [hwasan] Omit tag check for null pointers (PR #122206)

[Thurston Dang via llvm-commits]

thurstond wrote:

> Can you try to apply and measure code size change after the patch on some non-trivial binary, e.g. clang.

There are no instances of HWASan tag checks for provably-null pointers in clang (when bootstrapping revision b48b99f6253c917a15b698a68c1bf41d15ea6dc6).

https://github.com/llvm/llvm-project/pull/122206