test: Remove wallet option from non-wallet tests

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.

test/functional/wallet_multiwallet.py

@@ -52,6 +52,7 @@ class MultiWalletTest(BitcoinTestFramework):
         self.skip_if_no_wallet()
 
     def add_options(self, parser):
+        self.add_wallet_options(parser)
         parser.add_argument(
             '--data_wallets_dir',
             default=os.path.join(os.path.dirname(os.path.realpath(__file__)), 'data/wallets/'),