Stop using SkSpecialSurface in ImageFilterTest

Bug: b/299474380
Change-Id: I14995c4920307f093e198c48023ca0605634914d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/754656
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
1 file changed