Split components_tests into a separate gyp file

This enables us to depend on components from shell, since
components_tests already depends on shell.

BUG=none
R=joi@chromium.org

Review URL: https://codereview.chromium.org/34933002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230124 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230124