Gardening: Mark http/tests/security/cross-origin-worker-indexeddb-allowed.html as flaky crashing

TBR=mkwst@chromium.org
BUG=331586

Review URL: https://codereview.chromium.org/114773005

git-svn-id: svn://svn.chromium.org/blink/trunk@164472 bbb929c8-8fbe-4397-9dbb-9b2b20218538