Update SkiaPipelineTests.cpp to use new onNewImageSnapshot signature

Test: code compiles & test continues to succeed

https://skia-review.googlesource.com/c/9882/ (Remove budgeted parameter 
from SkSurface::makeImageSnapshot (take 2)) seems to have stuck so this 
should be safe to land.

Change-Id: I9e6fdcc8debe7964e9522f7acd8829b54bc90986