RAV reunification: MSPropertyRefExpr visitation

r179585 introduced different MSPropertyRefExpr visitation for RAV and DRAV that
appears to have been unintentional. Let's use the more complete one.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209101 91177308-0d34-0410-b5e6-96231b3b80d8