+ The kwargs dict is deep-copied, so it is safe to use the original
+ with partial modifications for subsequent commands.
+
+ Any pending conflicts from .api.json processing are raised.
+ Then the command name is checked for known CRCs.
+ Unsupported commands raise an exception, as CSIT change
+ should not start using messages without making sure which CRCs
+ are supported.
+ Each CRC issue is raised only once, so subsequent tests
+ can raise other issues.