Reland "remove bicubic clamp in SkImageShader"

This is a reland of bc9f3499c345ce59f8cd3889c580fa75db54034b
Original change's description:
> remove bicubic clamp in SkImageShader
> 
> We ought to be able to handle out-of-gamut colors now, whatever
> their provenance.  Should be we can just not clamp here.
> 
> Bug: skia:5733
> 
> Change-Id: Icd9851543638fd81755afee2eac2347702b88e9f
> Reviewed-on: https://skia-review.googlesource.com/87000
> Commit-Queue: Mike Klein <mtklein@chromium.org>
> Reviewed-by: Brian Osman <brianosman@google.com>

Bug: skia:5733
Change-Id: I66dafdb12abdb02e8677a6f6b18602a2fa3f5f8b
Reviewed-on: https://skia-review.googlesource.com/88760
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
2 files changed