Fix test flake in animation-event-destroy-renderer.
The ?animationiteration variant of the test could fail due to a stall
on the testing machine causing to animation to be finished before
animationiteration is fired. An animationiteration event does not fire
on the last iteration. Switched to a long duration animation with
setting the current time to trigger each event.
Tested locally with hundreds of repeats in virtual/threaded.
Bug: 355327241
Change-Id: I823ea9c3cb22c299e2f8c78ed0e051305827f404
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5740864
Reviewed-by: Robert Flack flackr@chromium.org
Commit-Queue: Kevin Ellis kevers@chromium.org
Cr-Commit-Position: refs/heads/main@{#1333517}