Remove display() from composited scrolling test, mark as failing

This test is testing some paint-dependent behavior (see issue 353827)
and should behave identically whether or not testRunner.display() is
called.  However, without the testRunner.display() calling into paint,
it misses some invalidations that need to be there for correctness.

BUG=345027,353827

Review URL: https://codereview.chromium.org/197883025

git-svn-id: svn://svn.chromium.org/blink/trunk@169575 bbb929c8-8fbe-4397-9dbb-9b2b20218538