Revert of Have GrRectBlurEffect use Linear filtering (rather than Nearest Neighbor) (patchset #1 id:1 of https://codereview.chromium.org/1378023004/ )

Reason for revert:
Failing some Blink layout tests - will wait until after branch.

Original issue's description:
> Have GrRectBlurEffect use Linear filtering (rather than Nearest Neighbor)
>
> Committed: https://skia.googlesource.com/skia/+/2d70bcccc9ba8f3898a7ae506ba7410ed8e9c9db

TBR=bsalomon@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1378323002
1 file changed