Mark two canvas tests as need rebaseline on Linux due to Skia change.

A recent Skia change that increases draw batching has resulted in minor pixel
diff.

TBR=junov@chromium.org
BUG=602509
NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2142273002
Cr-Commit-Position: refs/heads/master@{#404859}
1 file changed