FlakeSync: Automatically Repairing Async Flaky Tests

Regression testing is an important part of the development process but suffers from the presence of flaky tests. Flaky tests nondeterministically pass or fail when run on the same code, misleading developers about the correctness of their changes. A common type of flaky tests are async flaky tests that flakily fail due to timing-related issues such as asynchronous waits that do not return in time or different thread interleavings during execution. Developers commonly try to repair async flaky tests by inserting or increasing some wait time, but such repairs are unreliable.