[hwasan] Add test for hwasan pass with fixed shadow (#89813)

This test records the current behavior of HWASan, which doesn't utilize
the fixed shadow intrinsics of
https://github.com/llvm/llvm-project/commit/365bddf634993d5ea357e9715d8aacd7ee40c4b5

It is intended to be updated in future work ("Optimize outlined
memaccess for fixed shadow on Aarch64";
https://github.com/llvm/llvm-project/pull/88544)