If a C++ qualified id is followed by a postfix suffix, it is never the direct

operand of an addressof operator, and so we should not treat it as an abstract
member-pointer expression and therefore suppress the implicit member access.

This is really a well-formedness constraint on expressions:  a DeclRefExpr of
a FieldDecl or a non-static CXXMethodDecl (or template thereof, or unresolved
collection thereof) should not be allowed in an arbitrary location in the AST.
Arguably it shouldn't be allowed anywhere and we should have a different expr
node type for this.  But unfortunately we don't have a good way of enforcing
this kind of constraint right now.

llvm-svn: 89578