test/experiment_options_test.dart relies on "bogus" features defined by analyzer package #2156
Description
The test experiment_options_test.dart relies on the presence of two "bogus" entries in the analyzer's ExperimentStatus.knownFeatures map. These entries were not intended to be kept around in the long term; they were created solely to illustrate the file format while it was being developed. We should change the dartdoc test so that it doesn't require them. This could be accomplished, for example, by making use of the analyzer's overrideKnownFeatures method.
Making this change would allow us to address analyzer technical debt issue dart-lang/sdk#40860.