[clang][AArch64][FMV] Stop emitting alias to ifunc. (#96221)
Long story short the interaction of two optimizations happening in
GlobalOpt results in a crash. For more details look at the issue
https://github.com/llvm/llvm-project/issues/96197. I will be fixing this
in GlobalOpt but it is a conservative solution since it won't allow us
to optimize resolvers which return a pointer to a function whose
definition is in another TU when compiling without LTO:
```
__attribute__((target_version("simd"))) void bar(void);
__attribute__((target_version("default"))) void bar(void);
int foo() { bar(); }
```
fixes: #96197