Auto-retry integration tests as a bandaid

Created by: felixfbecker

This should prevent the flakiness of the integration tests (the symptom).

@sourcegraph/web This is a band-aid and we need to fix the real cause asap. It can cause us to merge changes that cause test failures in 50% of real-world cases because we will always grant it two tries. The only other alternative for a quickfix is disabling the integration tests completely though, and that would be worse.