Fix some issues handling sub-token locations that come from macro expansions.

We now emit:

t.m:6:15: warning: field width should have type 'int', but argument has type 'unsigned int'
  printf(STR, (unsigned) 1, 1);
         ^    ~~~~~~~~~~~~
t.m:3:18: note: instantiated from:
#define STR "abc%*ddef"
                 ^

which has the correct location in the string literal in the note line.

llvm-svn: 64936