improve diagnostics for C++ struct ; issues. Before:

t.cc:4:3: error: expected ';' at end of declaration list
  int y;
  ^
t.cc:6:1: error: expected ';' at end of declaration list
};
^

After:

t.cc:3:8: error: expected ';' at end of declaration list
  int x
       ^
       ;
t.cc:5:8: error: expected ';' at end of declaration list
  int z
       ^
       ;

llvm-svn: 95039