Mark 2 layout tests as flaky on other platforms
Mark 2 layout tests as flaky on other platforms

The following 2 tests are also flaky on other platforms:
virtual/threaded/transitions/transition-end-event-all-properties.html
virtual/threaded/transitions/move-after-transition.html

BUG=248938
TEST=none
TBR=dominicc@chromium.org

Review URL: https://codereview.chromium.org/23332013

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@156499 bbb929c8-8fbe-4397-9dbb-9b2b20218538

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk