[New Multicolumn] Skip tests in fast/multicol intended for region based multicolumns.

A bunch of tests in fast/multicol have baselines generated based on the
region based multicolumn implementation. These tests currently enable the
new multicolumn implementation via Javascript.

This patch skips those tests in the regular fast/multicol suite, leaving
virtual/regionbasedmulticol to run those tests instead. The test suite
virtual/regionbasedmulticol enables the new multicolumn behavior via a
command line flag, so it's no longer necessary to enable it via Javascript
(although they still ineffectively do that, for now).

Note that (ref)tests in fast/multicol/newmulticol/compare-with-old-impl
are special, because the they require the region based multicol
implementation in the test itself, and the old implementation in the
expected result. Hence, these tests should still run in the regular
fast/multicol suite.

BUG=334335
R=rune@opera.com

Review URL: https://codereview.chromium.org/343973002

git-svn-id: svn://svn.chromium.org/blink/trunk@177493 bbb929c8-8fbe-4397-9dbb-9b2b20218538