Remove duplicate method definitions in NodeConnCB subclasses

All Node classes in individual test cases subclass from NodeConnCB. Many
have duplicate definitions for methods that are defined in the base
class. This commit removes those duplicate definitions.

This commit removes ~290 lines of duplicate code.

test/functional/test_framework/comptool.py

@@ -192,7 +192,7 @@ class TestManager(object):
         return wait_until(disconnected, timeout=10)
 
     def wait_for_verack(self):
-        [node.wait_for_verack() for node in self.test_nodes]
+        return all(node.wait_for_verack() for node in self.test_nodes)
 
     def wait_for_pings(self, counter):
         def received_pongs():

test/functional/test_framework/mininode.py

@@ -1590,34 +1590,25 @@ class NodeConnCB(object):
 
     # Message receiving helper methods
 
-    def sync(self, test_function, timeout=60):
-        while timeout > 0:
-            with mininode_lock:
-                if test_function():
-                    return
-            time.sleep(0.05)
-            timeout -= 0.05
-        raise AssertionError("Sync failed to complete")
-
     def wait_for_block(self, blockhash, timeout=60):
         test_function = lambda: self.last_message.get("block") and self.last_message["block"].block.rehash() == blockhash
-        self.sync(test_function, timeout)
+        assert wait_until(test_function, timeout=timeout)
 
     def wait_for_getdata(self, timeout=60):
         test_function = lambda: self.last_message.get("getdata")
-        self.sync(test_function, timeout)
+        assert wait_until(test_function, timeout=timeout)
 
     def wait_for_getheaders(self, timeout=60):
         test_function = lambda: self.last_message.get("getheaders")
-        self.sync(test_function, timeout)
+        assert wait_until(test_function, timeout=timeout)
 
     def wait_for_inv(self, expected_inv, timeout=60):
         test_function = lambda: self.last_message.get("inv") and self.last_message["inv"] != expected_inv
-        self.sync(test_function, timeout)
+        assert wait_until(test_function, timeout=timeout)
 
     def wait_for_verack(self, timeout=60):
         test_function = lambda: self.message_count["verack"]
-        self.sync(test_function, timeout)
+        assert wait_until(test_function, timeout=timeout)
 
     # Message sending helper functions
 
@@ -1635,12 +1626,9 @@ class NodeConnCB(object):
     def sync_with_ping(self, timeout=60):
         self.send_message(msg_ping(nonce=self.ping_counter))
         test_function = lambda: self.last_message.get("pong") and self.last_message["pong"].nonce == self.ping_counter
-        success = wait_until(test_function, timeout = timeout)
-        if not success:
-            logger.error("sync_with_ping failed!")
-            raise AssertionError("sync_with_ping failed!")
+        assert wait_until(test_function, timeout=timeout)
         self.ping_counter += 1
-        return success
+        return True
 
 # The actual NodeConn class
 # This class provides an interface for a p2p connection to a specified node