Ping regularly in p2p-segwit.py to keep connection alive

This pings regularly while building a big block in p2p-segwit.py, to prevent timeout

qa/rpc-tests/p2p-segwit.py

@@ -1392,6 +1392,9 @@ class SegWitTest(BitcoinTestFramework):
         block = self.build_next_block()
         used_sighash_single_out_of_bounds = False
         for i in range(NUM_TESTS):
+            # Ping regularly to keep the connection alive
+            if (not i % 100):
+                self.test_node.sync_with_ping()
             # Choose random number of inputs to use.
             num_inputs = random.randint(1, 10)
             # Create a slight bias for producing more utxos