Fix a bug in SkGpuBlurUtils::GaussianBlur (take 3)

This fixes the remaining imageblurclampmode bug and a preexisting un-reported error in the imageblurrepeatmode GM.

This relies on https://chromium-review.googlesource.com/c/chromium/src/+/1044113 (Add a flag to disable a blur imagefilter bug fix in Skia) landing in Chrome first.

Bug: skia:7765
Change-Id: I66e27384541002829b2bd4b42d9cbda837aa7c3d
Reviewed-on: https://skia-review.googlesource.com/125961
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-on: https://skia-review.googlesource.com/126220
1 file changed