remove bench -- we don't exercise this class anymore

Change-Id: I86b4cee170028278f2ce5ea0398c0b387b1b7724
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/272725
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
1 file changed