Mark combo-transform-translate+scale.html flaky on release

Mark animations/combo-transform-translate+scale.html as flaky for all
configurations as the flakiness isn't limited to DEBUG builds.

TBR=jianli
BUG=

Review URL: https://codereview.chromium.org/68263006

git-svn-id: svn://svn.chromium.org/blink/trunk@161739 bbb929c8-8fbe-4397-9dbb-9b2b20218538