[Clang][Sema] Avoid crashing for `__builtin_memcpy_inline` with an array argument

This change teaches the Sema logic for `__builtin_memcpy_inline` to implicitly convert arrays passed as arguments to pointers, similarly to regular `memcpy`.

This code will no longer cause a compiler crash:
```
void f(char *p) {
    char s[1] = {0};
    __builtin_memcpy_inline(p, s, 1);
}
```

rdar://88147527

Differential Revision: https://reviews.llvm.org/D121475