Automatically retry flaky tests

Use splitics -flaky option to automatically retry flaky tests. The list of flaky tests is defined in .flaky-tests.txt, where each line is the full go test case path (the path that is printed if one runs go test with -v). Failing test listed in the file are retried up to three times.

This list was generated by pulling the logs for last 100 failed "test" CI jobs (unit/integration, linux/windows), and running them through the expression:

rg -I "\--- FAIL:" traces/ | cut -d " " -f 5 | sort -u  

Then pruning the result to the actual test cases that failed.

Relates to gitlab-runner pipelines are unreliable (#39338 - closed)