* Added support for authentication codes for the VM service.
Previously, a valid web socket connection would use the following URI:
`ws://127.0.0.1/ws`
Now, by default, the VM service requires a connection to be made with a
URI similar to the following:
`ws://127.0.0.1:8181/Ug_U0QVsqFs=/ws`
where `Ug_U0QVsqFs` is an authentication code generated and shared by
the
service.
This behavior can be disabled with the `--disable-service-auth-codes`
flag.
* Upgrade everything except matcher.
* Roll matcher (and test)
* Adjust tests that depend on flutter:test directly to depend on a shim
* Require use of package:test shim and remove other references to package:test