tests: ensure functional tests set permitbaremultisig=1 when needed

The mempool_dust and mempool_sigoplimits functional tests both use bare
multisig txs, so ensure they're allowed by policy.

test/functional/mempool_sigoplimit.py

@@ -140,7 +140,7 @@ class BytesPerSigOpTest(BitcoinTestFramework):
         self.log.info("Test a overly-large sigops-vbyte hits package limits")
         # Make a 2-transaction package which fails vbyte checks even though
         # separately they would work.
-        self.restart_node(0, extra_args=["-bytespersigop=5000"] + self.extra_args[0])
+        self.restart_node(0, extra_args=["-bytespersigop=5000","-permitbaremultisig=1"] + self.extra_args[0])
 
         def create_bare_multisig_tx(utxo_to_spend=None):
             _, pubkey = generate_keypair()