Objective-C (mostly arc): Under ARC, we often have unneeded qualifiers 
in the diagnostics. Remove them when reporting incompatible
Objective-C pointer types. // rdar://13752880.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180765 91177308-0d34-0410-b5e6-96231b3b80d8