beef-up paint-vs-font metrics test

Bug: skia:
Change-Id: Ie59ad9707e1fb25ae70b40f07babf37351edb102
Reviewed-on: https://skia-review.googlesource.com/c/171535
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Herb Derby <herb@google.com>
1 file changed