Disable CrExtensionsToolbarTest.ClickHandlers on non-macos

Disabling this test as it regularly (~50% of times) times out on Linux and
Windows. The test is fine on MacOS.

TBR=rdevlin.cronin@chromium.org

Bug: 882342
Change-Id: I23dd794332f57cbbd46ba167efc562041f7e9dff
Reviewed-on: https://chromium-review.googlesource.com/1215284
Reviewed-by: Dominic Battré <battre@chromium.org>
Commit-Queue: Dominic Battré <battre@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589862}
1 file changed