My thinking is that this may reduce the cognitive overhead for
developers writing new test suites.
This also allows us to perform different setup steps (like ensuring the
editor is visible when authenticated).
This uses the current dev build by default but can be overidden with
CODE_SERVER_TEST_ENTRY (for example to test a release or some other
version).
Each instance has a separate state directory. This should make
parallelization work.
This also means you are no longer required to specify the password and
address yourself (or the extension directory once we add a test
extension). `yarn test:e2e` should just work as-is.
Lastly, it means the tests are no longer subject to yarn watch randomly
restarting.
