Clean up/remove unused GrFragmentProcessor-derived ctors

This is the simple (i.e., non-TextureAdjuster) portion of: https://skia-review.googlesource.com/c/8823/ (Remove GrFragmentProcessor-derived class' GrTexture-based ctors)

Change-Id: I8f673ebe922e03c69473c18c166bcf818507c662
Reviewed-on: https://skia-review.googlesource.com/8997
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
27 files changed