[HWASan] fix missing BTI attribute on personality function thunks (#139138)
This used to work because the BTI attribute was taken from the module in
the CodeGen.
e15d67cfc2e5775cc79281aa860f3ad3be628f39 changed that to actually look
at the function attributes. This led to crashes for BTI, because we did
not emit the proper landing pads for the thunk.