Mark console-uncaught-promise.js as flaky

Bug: 1244038
Change-Id: I60704b9279330766de2ff72194305822c13cd39b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3123424
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Commit-Position: refs/heads/main@{#915922}