Split the cubic and quad into separate fuzzers

This will allow an error bounds checking fuzzer for
quad.

Bug: skia:14252
Change-Id: I3f2a1a1d78ac0b775d73ee261ebc9981ef927300
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/699788
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
5 files changed