Remove tests that no longer make sense post-Blinking.

These test that grid and regions are not enabled by default on trunk,
but we run test with experimental features enabled, so these are
enabled when running the tests.

TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/22405007

git-svn-id: svn://svn.chromium.org/blink/trunk@155912 bbb929c8-8fbe-4397-9dbb-9b2b20218538