Remove old GrFillRectOp factories

Also renames MakeGeneric() back to Make() and updates tests

Change-Id: I493c40d84ef1a075bddca72939f46a81bea5dea7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/215091
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
4 files changed