Allow registering MNs without actually starting them

This can be done by calling prepare_masternode() when inside run_test.
Also implement remove_masternode() which spends the collateral.

qa/rpc-tests/test_framework/test_framework.py

@@ -277,6 +277,9 @@ class DashTestFramework(BitcoinTestFramework):
 
     def prepare_masternodes(self):
         for idx in range(0, self.mn_count):
+            self.prepare_masternode(idx)
+
+    def prepare_masternode(self, idx):
         bls = self.nodes[0].bls('generate')
         address = self.nodes[0].getnewaddress()
         txid = self.nodes[0].sendtoaddress(address, MASTERNODE_COLLATERAL)
@@ -308,6 +311,15 @@ class DashTestFramework(BitcoinTestFramework):
         self.mninfo.append(MasternodeInfo(proTxHash, ownerAddr, votingAddr, bls['public'], bls['secret'], address, txid, collateral_vout))
         self.sync_all()
 
+    def remove_mastermode(self, idx):
+        mn = self.mninfo[idx]
+        rawtx = self.nodes[0].createrawtransaction([{"txid": mn.collateral_txid, "vout": mn.collateral_vout}], {self.nodes[0].getnewaddress(): 999.9999})
+        rawtx = self.nodes[0].signrawtransaction(rawtx)
+        self.nodes[0].sendrawtransaction(rawtx["hex"])
+        self.nodes[0].generate(1)
+        self.sync_all()
+        self.mninfo.remove(mn)
+
     def prepare_datadirs(self):
         # stop faucet node so that we can copy the datadir
         stop_node(self.nodes[0], 0)