clang was encoding pointers to typedefs as if they were pointers to
structs because that is apparently what gcc is doing.
For example:
```
@class Class1;
typedef NSArray<Class1 *> MyArray;
void foo1(void) {
const char *s0 = @encode(MyArray *); // "^{NSArray=#}"
const char *s1 = @encode(NSArray<Class1 *> *); // "@"
}
```
This commit removes the code that was there to make clang compatible
with gcc and make clang emit the correct encoding for ObjC pointers,
which is "@".
rdar://problem/50563529
Differential Revision: https://reviews.llvm.org/D61974
llvm-svn: 362034