Early Exit Failing Mac Fling Tests on Viz

There are two remaining Mac Fling tests which fail under Viz. Work is
ongoing to land a fix, but there was flakiness if the resolution.

This change updates the failing tests to exit early when it is Viz on
Mac. This will unblock removing our filter files.

TEST=BrowserSideFlingBrowserTest.TouchpadFling
BrowserSideFlingBrowserTest.TouchscreenFling

Bug: 842325
Change-Id: I67e7c6165d821c9df4907ebf8803fe22fbdf1663
Reviewed-on: https://chromium-review.googlesource.com/1151392
Reviewed-by: ccameron <ccameron@chromium.org>
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578362}
1 file changed