Remove excessive use of Carbon.h / Cocoa.h in clang tests.

 - These kinds of "shotgun" tests are very slow, and do not belong in the
   regression suite. If these kinds of tests are regarded to have value, they
   should be added to the LLVM test-suite.

 - I would actually like to remove all of these tests, but I left Sema/carbon.c
   and SemaObjC/cocoa.m...

llvm-svn: 75399