Adds diagnosing on attempt to use zero length arrays, pointers, refs, arrays
of them and structs/classes containing all of it.
In case a struct/class with zero length array is used this emits a set
of notes pointing out how zero length array got into used struct, like
this:
```
struct ContainsArr {
int A[0]; // note: field of illegal type declared here
};
struct Wrapper {
ContainsArr F; // note: within field of type ContainsArr declared here
// ...
}
// Device code
Wrapper W;
W.use(); // error: zero-length arrays are not permitted
```
Total deep check of each used declaration may result in double
diagnosing at the same location.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D114080
Fangrui Song