Remove support for reading old serialized SkVertices

Change-Id: If3010945532e1d6b16e590cf8c4afd4578ae770f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/285392
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed