This commit updates the code by replacing the RPC call used to
decode an address and retrieve its corresponding scriptpubkey
with the address_to_scriptpubkey function. address_to_scriptpubkey
function can now decode all addresses formats, which makes
it more efficient to use.
Review note: The changes are complete, because self.options.descriptors
is set to None in parse_args (test_framework.py).
A value of None implies -disablewallet, see the previous commit.
So if a call to add_wallet_options is missing, it will lead to a test
failure when the wallet is compiled in.
