Remove dead store.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178561 91177308-0d34-0410-b5e6-96231b3b80d8
Objective-C: Provide fixit hints when warning
about 'isa' ivar being explicitely accessed
when base is a user class object reference.
// rdar://13503456


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178562 91177308-0d34-0410-b5e6-96231b3b80d8