wallet: Switch to using ancestor/descendant limits
wallet: Switch to using ancestor/descendant limits

Instead of combining the -limitancestorcount and -limitdescendantcount into a nMaxChainLength, this commit uses each one separately in the coin eligibility filters.

chaincoin/chaincoin,chaincoin/chaincoin,chaincoin/chaincoin,chaincoin/chaincoin,chaincoin/chaincoin,chaincoin/chaincoin