Fix cached perspective shadows

Bug: b/123261126
Change-Id: Ia1b6d4971c89b5bd328c8ff7c2090c55cc2cd424
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201382
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
1 file changed