Fix test data copying on iOS

Fix test data copying on iOS

gyp can cache and re-use the output of scripts that have the same
invocation, and all the test data copying uses "test/data". This is
a relative path, so it's not really the same command, causing flaky
compile failures.

This works around the bug by artificially introducing variation into
the invocation string.

NOTRY=true
BUG=369533
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=267919

[stuartmorgan, 2014-05-02 19:29:14]

Forgot Lane is a committer; re-routing review.

[Nico, 2014-05-02 19:44:27]

lgtm

[stuartmorgan, 2014-05-02 19:47:57]

The CQ bit was checked by stuartmorgan@chromium.org

[commit-bot: I haz the power, 2014-05-02 19:48:17]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/stuartmorgan@chromium.org/265043003/1

[commit-bot: I haz the power, 2014-05-02 20:01:58]

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

[commit-bot: I haz the power, 2014-05-02 20:01:58]

Try jobs failed on following builders:
  linux_chromium_chromeos_rel on tryserver.chromium

[stuartmorgan, 2014-05-02 20:05:56]

The CQ bit was checked by stuartmorgan@chromium.org

[commit-bot: I haz the power, 2014-05-02 20:06:23]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/stuartmorgan@chromium.org/265043003/1

[commit-bot: I haz the power, 2014-05-02 20:12:55]

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

[commit-bot: I haz the power, 2014-05-02 20:12:56]

Try jobs failed on following builders:
  mac_chromium_rel on tryserver.chromium

[stuartmorgan, 2014-05-02 20:42:13]

The CQ bit was checked by stuartmorgan@chromium.org

[commit-bot: I haz the power, 2014-05-02 20:42:40]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/stuartmorgan@chromium.org/265043003/1

[commit-bot: I haz the power, 2014-05-02 21:16:14]

Change committed as 267919