TestExpectations: Added more flaky platforms for virtual/threaded/animations/fill-mode-iteration-count-non-integer.html

BUG=248938
TBR=shawnsingh@chromium.org

Review URL: https://codereview.chromium.org/23566011

git-svn-id: svn://svn.chromium.org/blink/trunk@156867 bbb929c8-8fbe-4397-9dbb-9b2b20218538