Remove lingering -webkit-svg-shadow tests

Remove lingering -webkit-svg-shadow tests

-webkit-svg-shadow support was removed in r154982 (tracked in issue
262857), but leaving these three tests behind (two of which would
trivially pass because they were ref tests.)

BUG=262857, 223332
Committed: https://crrev.com/88e7842501ac875ace9c5cbf3975a94bd8b4e90c
Cr-Commit-Position: refs/heads/master@{#352332}

[fs, 2015-10-05 12:39:18]

fs@opera.com changed reviewers:
+ pdr@chromium.org, schenney@chromium.org

[Stephen Chennney, 2015-10-05 15:36:06]

The CQ bit was checked by schenney@chromium.org

[Stephen Chennney, 2015-10-05 15:36:07]

lgtm

[commit-bot: I haz the power, 2015-10-05 15:36:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1387823003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1387823003/1

[commit-bot: I haz the power, 2015-10-05 15:45:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-10-05 15:45:49]

Try jobs failed on following builders:
  linux_chromium_clobber_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Stephen Chennney, 2015-10-05 16:21:49]

The CQ bit was checked by schenney@chromium.org

[commit-bot: I haz the power, 2015-10-05 16:23:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1387823003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1387823003/1

[commit-bot: I haz the power, 2015-10-05 16:30:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-05 16:31:35]

Patchset 1 (id:??) landed as
https://crrev.com/88e7842501ac875ace9c5cbf3975a94bd8b4e90c
Cr-Commit-Position: refs/heads/master@{#352332}