Revise update-w3c-deps to check in tests directly

As discussed on blink-dev, we will start checking in the imported w3c tests directly.

This is patchset 1 of 4 in making that happen.

This patch changes update-w3c-deps to do the import. Tests will now be imported into the "LayoutTests/imported" directory, to avoid any conflicts with the old git repos.

This patch significantly reworks update-w3c-deps, and patches webkitpy.test_importer to remove the import logs, make logging work better during the import, and handle skipping subdirs properly when not importing in place.

This patch also adds an exit() method to the SystemHost class to remove one more reason for importing sys.

TBR=eseidel@chromium.org
BUG=413454
BUG=

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181860

[Dirk Pranke, 2014-09-11 22:09:34]

clean up update-w3c-deps

[Dirk Pranke, 2014-09-11 22:54:17]

Patchset #1 (id:1) has been deleted

[Dirk Pranke, 2014-09-11 22:54:24]

Patchset #1 (id:20001) has been deleted

[Dirk Pranke, 2014-09-11 23:01:51]

dpranke@chromium.org changed reviewers:
+ eseidel@chromium.org

[Dirk Pranke, 2014-09-11 23:02:13]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2014-09-11 23:02:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/565673006/40001

[commit-bot: I haz the power, 2014-09-12 00:19:28]

Committed patchset #1 (id:40001) as 181860