Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)
Changes made by clang-tidy with minor tweaks.
llvm-svn: 215558
This was missed since whenever I was including ObjCARCAliasAnalysis.h, I
was including ObjCARC.h before it which included these includes
(resulting in no compilation breakage).
llvm-svn: 173764