Revert "Remove interpolants are inaccurate workaround for Adreno 3xx."

This reverts commit a7a278205bb040061cb4ba46839efe18635c7edc.

Reason for revert: Chrome change had to be reverted because of new failures on Nexus 9 and 6P.

Original change's description:
> Remove interpolants are inaccurate workaround for Adreno 3xx.
> 
> The chrome screenshot unit test that led to adding this workaround has
> been adjusted to avoid testing AA edges of rendered rectangles. We're
> accepting the inaccuracy in favor of increased performance.
> 
> Chrome change: https://chromium-review.googlesource.com/c/chromium/src/+/1129041
> 
> Bug: chromium:847984
> Change-Id: I9b714ade2a67e956ebb2773ebe3b8632dc3a50c6
> Reviewed-on: https://skia-review.googlesource.com/140180
> Commit-Queue: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>
> Auto-Submit: Brian Salomon <bsalomon@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>

TBR=bsalomon@google.com,brianosman@google.com

Change-Id: Ic6b0e5a343556e59d144852f9fa5b561302f9781
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:847984
Reviewed-on: https://skia-review.googlesource.com/140380
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
4 files changed