flutter_tools/test/src/context.dart has non-mock "Mock*" classes #33274

There are various classes in context.dart that are called Mock* but are not actually mocks. It seems random, and possibly just an oversight. For instance:
class MockXcodeProjectInterpreter implements XcodeProjectInterpreter
but
class MockIOSSimulatorUtils extends Mock implements IOSSimulatorUtils
This is bug number 1.

It looks like they are intended for use in the default testUsingContext, but are public (I would argue that being public is bug number 2).

Taking the MockXcodeProjectInterpreter example, test files that actually want to mock that class have:
class MockXcodeProjectInterpreter extends Mock implements XcodeProjectInterpreter {}
This shadows the version in context.dart (bug number 3).

When you put all this together, you end up with the very surprising behavior that if you take a working test using a local MockXcodeProjectInterpreter and move it to a new file, but neglect to add a local override in that new file, everything compiles just fine and you get mysterious Mock method was not called within 'when()' errors and waste a lot of time trying to figure out what's going on.

I would argue that at a minimum

1. Classes named Mock* need to be Mock objects.
2. context.dart shouldn't be vending objects that are being silently shadowed in test files.