Remove some TestExpectations lines related to -webkit-canvas tests

Remove some TestExpectations lines related to -webkit-canvas tests

https://codereview.chromium.org/1416793004 deleted the -webkit-canvas
feature along with the related tests, but some traces were left behind
in TestExpectations

BUG=485332
TBR=chrishtr@chromium.org
NOTRY=true

Committed: https://crrev.com/9edb8419cd968c50227bcb928d9adb3e8f58d283
Cr-Commit-Position: refs/heads/master@{#357927}

[Justin Novosad, 2015-11-04 23:11:23]

The CQ bit was checked by junov@chromium.org

[commit-bot: I haz the power, 2015-11-04 23:11:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1421893006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1421893006/1

[chrishtr, 2015-11-04 23:24:55]

lgtm

[commit-bot: I haz the power, 2015-11-04 23:25:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-04 23:26:46]

Patchset 1 (id:??) landed as
https://crrev.com/9edb8419cd968c50227bcb928d9adb3e8f58d283
Cr-Commit-Position: refs/heads/master@{#357927}