This is basically just using the new check_dict_only everywhere, with
a few exceptions:
* New self.check_events_dict automatically adds the id field to avoid
duplicating it ~80 times.
* Set log=False for many of the testing action functions to remove the
timestamp field from their returned event dictionaries, since it's
not needed and is the result of a deprecated log_event function.
Wasn't sure if the subscription_field list in do_test_subscribe_events
could contain optional arguments, so I left the call to check_dict on
along with a TODO.
Fixes: #1370.
854d70e7c6