Diagnose misordered initializers in constructor templates immediately instead of

when they're instantiated.  Merge the note into the -Wreorder warning;  it
doesn't really contribute much, and it was splitting a thought across diagnostics
anyway.  Don't crash in the parser when a constructor's initializers end in a
comma and there's no body;  the recovery here is still terrible, but anything's
better than a crash.

llvm-svn: 100922