Skip unnecessary moveTo in degenerate quad calculations

Change-Id: If73951f8e183101b80f729d9533cc3c8395b1879
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/252481
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
2 files changed