Assert that RPCArg names are equal to CRPCCommand ones (abc, avalanche)

Summary:

Motivation

RPCArg names in the rpc help are currently only used for documentation. However, in the future they could be used to teach the server the named arguments. Named arguments are currently registered by the CRPCCommands and duplicate the RPCArg names from the documentation. This redundancy is fragile, and has lead to errors in the past (despite having linters to catch those kind of errors). See section D10741 for a list of bugs that have been found as a result of the changes here.

The changes here add an assert in the CRPCCommand constructor that the RPCArg names are identical to the ones in the CRPCCommand.

This should be the final diff related to core#18531.

Depends on D10741

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10742