Disable TabDragController tests that fail with a real compositor.

These tests fail with --disable-test-compositor or with
the https://codereview.chromium.org/120313002/ CL applied.
Since this is blocking making all browser tests use a real
composited path, disable these tests for now.

Some tests can be made to work by waiting for the tab drag
action to start/finish, so do that to avoid disabling those
tests.

R=sadrul@chromium.org, sky
BUG=331924,270918

Review URL: https://codereview.chromium.org/140793006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245902 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245902