Add a fixed-count impl for tessellated wedges

Bug: skia:10419
Change-Id: Ibb5adb581045e98cb636006aa84f792847041ca5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/416856
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
13 files changed