Fix PR9279 - Macro expansion stack trace seriously broken with function-style...

Fix PR9279 - Macro expansion stack trace seriously broken with function-style macros, by not recursively printing notes for other 'instantiated from' notes.

This is a one line fix here:
+      // Don't print recursive instantiation notes from an instantiation note.
+      Loc = SM.getSpellingLoc(Loc);

While here, fix the testcase to be more precise (it got filecheck'ized
brutally), and fix EmitCaretDiagnostic to be private and to not pass down
the unused 'Level' argument.

llvm-svn: 133993