Revert "Use raster pipeline for repeat/mirror radial gradients"

This reverts commit 2f924b4b0e5d364d608e181da8270241038de6c9.

Reason for revert: IOS nanobench crashes

Original change's description:
> Use raster pipeline for repeat/mirror radial gradients
> 
> The legacy clamp specialization is still faster, but for repeat and
> mirror RP wins (at low color stop counts).
> 
> Change-Id: Ifef3eb5b3111b3741d3a033310a4cdb58e592247
> Reviewed-on: https://skia-review.googlesource.com/24283
> Reviewed-by: Mike Reed <reed@google.com>
> Commit-Queue: Florin Malita <fmalita@chromium.org>

TBR=mtklein@google.com,herb@google.com,fmalita@chromium.org,reed@google.com

Change-Id: I65db31b149b6b2507cbe470049f67774e3bf40a0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/24660
Reviewed-by: Florin Malita <fmalita@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
2 files changed