Move rebaseline-all command from the gardening-server down into webkit-patch

Move rebaseline-all command from the gardening-server down into webkit-patch
https://bugs.webkit.org/show_bug.cgi?id=90395

Reviewed by Adam Barth.

This is just moving code. It it in preparation for making rebaseline-expectations
use the same code in order to get the parallelism benefits and reduces the amount
of code we have for doing rebaselines.

* Scripts/webkitpy/common/checkout/checkout_unittest.py:
(CheckoutTest.test_apply_patch):
Updated due to the change to executive_mock.
* Scripts/webkitpy/common/system/executive_mock.py:
(MockExecutive.run_command):
Update to print out the input passed to stdin.
* Scripts/webkitpy/tool/commands/download_unittest.py:
Updated due to executive_mock change.
* Scripts/webkitpy/tool/commands/rebaseline.py:
(RebaselineAll):
(RebaselineAll._run_webkit_patch):
(RebaselineAll._builders_to_fetch_from):
(RebaselineAll._rebaseline_commands):
(RebaselineAll._files_to_add):
(RebaselineAll._optimize_baselines):
(RebaselineAll._rebaseline):
(RebaselineAll.execute):
All this code is just copy-pasted except for mechanical changes
(e.g. self.server.tool --> self._tool) and the reading in of the
JSON from stdin instead of the post body.
* Scripts/webkitpy/tool/commands/rebaseline_unittest.py:
(test_rebaseline_all):
Copied the test-case out of gardeningserver_unittest.py.
* Scripts/webkitpy/tool/servers/gardeningserver.py:
(GardeningHTTPRequestHandler):
(GardeningHTTPRequestHandler.rebaseline):
(GardeningHTTPRequestHandler.rebaselineall):
* Scripts/webkitpy/tool/servers/gardeningserver_unittest.py:
(GardeningServerTest.test_rebaselineall):
(GardeningServerTest.test_rebaselineall.run_command):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@121699 268f45cc-cd09-0410-ab3c-d52691b4dbfc