message: [tests] Remove deprecated addwitnessaddress call from feature_nulldummy
  addwitnessaddress is deprecated. Replace the call to addwitnessaddress
  with a call to getnewaddress(address_type='p2sh-segwit')
diff: @@ -41,7 +41,7 @@ class NULLDUMMYTest(BitcoinTestFramework):
  self.setup_clean_chain = True
  # This script tests NULLDUMMY activation, which is part of the 'segwit' deployment, so we go through
  # normal segwit activation here (and don't use the default always-on behaviour).
  - self.extra_args = [['-whitelist=127.0.0.1', '-vbparams=segwit:0:999999999999', '-addresstype=legacy', "-deprecatedrpc=addwitnessaddress"]]
  + self.extra_args = [['-whitelist=127.0.0.1', '-vbparams=segwit:0:999999999999', '-addresstype=legacy']]
  def skip_test_if_missing_module(self):
  self.skip_if_no_wallet()
  @@ -49,7 +49,7 @@ class NULLDUMMYTest(BitcoinTestFramework):
  def run_test(self):
  self.address = self.nodes[0].getnewaddress()
  self.ms_address = self.nodes[0].addmultisigaddress(1, [self.address])['address']
  - self.wit_address = self.nodes[0].addwitnessaddress(self.address)
  + self.wit_address = self.nodes[0].getnewaddress(address_type='p2sh-segwit')
  self.wit_ms_address = self.nodes[0].addmultisigaddress(1, [self.address], '', 'p2sh-segwit')['address']
  self.coinbase_blocks = self.nodes[0].generate(2) # Block 2
  