Automatically create issues with relevant group label for all test failures in master

Inspired by https://github.blog/2020-12-16-reducing-flaky-builds-by-18x/ and https://github.com/dmagliola/faster_ci, we should create a system to surface the most problematic flaky tests by creating issues automatically (similarly to how we do it for end-to-end failures) for each failed test in master. This is so that we already have issues later on to track the flaky tests, and that'll be helpful when we start using the Confiner tool to auto-quarantine flaky tests (#361672 (closed)).