[libclang] When indexing a @synthesize, don't consider that it defines a getter/setter if one is already defined by the user.

Fixes rdar://13925258

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182895 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed