Remove code for Chromium from wkbuild.py
https://bugs.webkit.org/show_bug.cgi?id=114423

Reviewed by Benjamin Poulain.

* BuildSlaveSupport/build.webkit.org-config/wkbuild.py:
(_should_file_trigger_build):
* BuildSlaveSupport/build.webkit.org-config/wkbuild_unittest.py:
(ShouldBuildTest):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148190 268f45cc-cd09-0410-ab3c-d52691b4dbfc