RestarterTests should not rely on the test runner using a static method named main #15461
Description
Currently, DevTools' RestarterTests rely on the test runner having a static method named main that is in the stack when the Restarter instance is created. This holds true in Eclipse and IntelliJ and when run using Surefire but it may not always do so. We should make things clearer by modifying the tests to ensure that a static method named main is in the stack during Restarter creation.