fix: await handlePullRequest in rerunCheck and correct asyncs in tests

Proposed Changes

test 'check_run rerequested' added to test it
test methods that should be async made async
commentOnPull made true to also test the appropriate code path
handlePullRequest in tests replaced with handlePullRequestWithRally to escape creating real rally instance, that runs its own asyncs, that are left after the tesrts are over
setup.js with fail on unhandledRejection added to catch async warnings like the one appeared with the absent Connections._ref in rallyClient

[x] If this change requires documentation, it has been included in this pull request

[x] If a functional change has occurred, testing the integration has been performed
[ ] This PR has been categorized with a label (1 of automation, bug, documentation, enhancement, infrastructure, or performance) for the changelog