Add new GM to test hairline subdivision.

As I'm changing the subdivision method, I want to have a baseline to
make sure I don't break anything.

Change-Id: I655c658589c7229ae37d7b8588ff70325afeaa61
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/302907
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
1 file changed