Mark jump-to-previous-editing-location.html and xss-DENIED-to-data-url-in-foreign-domain-subframe-location-change.html flaky.

BUG=352464,352466
TBR=zmo@chromium.org

Review URL: https://codereview.chromium.org/199813002

git-svn-id: svn://svn.chromium.org/blink/trunk@169191 bbb929c8-8fbe-4397-9dbb-9b2b20218538