Fixes #463 - Fix rules for checking if pipeline should run in "flaky" mode or not

Previous Commit contained a bug that didn't work on pipeline because of poor shell on the runners. I've improved whole logic so now:

• pipeline will run only tests marked as flaky in title, but check will be done in shell script inside docker entrypoint,
• automatically it will trigger 30 test but can be changed by adding number to [flaky] parameter, f.ex" [flaky 10] in Commit message or MODE parameter on docker run.
• devs can run locally same setup by passing -MODE=[flaky] when running docker