In Objective-C ARC, completely ignore ownership qualifiers on the
return type of a function by canonicalizing them away. They are
useless anyway, and conflict with our rules for template argument
deduction and __strong. Fixes <rdar://problem/12367446>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172768 91177308-0d34-0410-b5e6-96231b3b80d8