clang -fsanitize=alignment crashes with __builtin_assume_aligned

```C
// clang -c -fsanitize=alignment test.c
int main ()
{
(void) __builtin_assume_aligned("", 1);
  return 0;
}
```



```console
llvm/llvm-project/clang/include/clang/AST/Type.h:691: const ExtQualsTypeCommonBase *clang::QualType::getCommonPtr() const: Assertion `!isNull() && "Cannot retrieve a NULL type pointer"' failed.
```

@vitalybuka can you please check?