Change PerspectiveClip to clip directly to half plane.

This should be a little more numerically stable, and avoids the need
for the assert.

Bug: chromium:1032435
Change-Id: I038890000b251f3ffed41f37a14451afcf3b1866
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/259167
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
1 file changed