[clang] Change builtin object size when subobject is invalid

[clang] Change builtin object size when subobject is invalid

Motivating example:

```
  struct { int v[10]; } t[10];

  __builtin_object_size(
      &t[0].v[11], // access past end of subobject
      1            // request remaining bytes of closest surrounding
                   // subobject
  );
```

In GCC, this returns 0. https://godbolt.org/z/7TeGs7

In current clang, however, this returns 356, the number of bytes
remaining in the whole variable, as if the `type` was 0 instead of 1.
https://godbolt.org/z/6Kffox

This patch checks for the specific case where we're requesting a
subobject's size (type 1) but the subobject is invalid.

Differential Revision: https://reviews.llvm.org/D92892