Pass the correct object argument when a member call to an 'unrelated' class is made.

Prior to this patch, clang would do the wrong thing here (see inline comments for pre-patch behavior):

  struct A {
    void bar(int) { }
    static void bar(double) { }
    
    void g(int*);
    static void g(char *);
  };


  struct B {
    void f() {
      A::bar(3);  // selects (double) ??!!
      A::g((int*)0); // Instead of no object argument, states conversion error?!!
    }
  };


The fix is as follows:  When we detect that what appears to be an implicit member function call (A::bar) is actually a call to a member of a class (A) unrelated to the type (B) that contains the member function (B::f) from which the call is being made, don't treat it (A::bar) as an Implicit Member Call Expression.

P.S. I wonder if there is an existing bug report related to this? (Surprisingly, a cursory search did not find one).

llvm-svn: 311839