Fix ObjCMethodDecl::findPropertyDecl for class properties.

This affects code completion and a few other things; hopefully the code completion
test is sufficient to catch regressions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@263295 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed