test: bump mocktime after node has received and sent bytes

a different error message "socket no message in first %i seconds"
will be displayed if m_last_send=0 or if m_last_recv is 0. make
the test robust by ensuring that they will not be 0 before
bumping mocktime.

test/functional/p2p_v2_misbehaving.py

@@ -147,9 +147,10 @@ def test_earlykeyresponse(self):
         peer1.v2_state.can_data_be_received = True
         self.wait_until(lambda: peer1.v2_state.ellswift_ours)
         peer1.send_raw_message(peer1.v2_state.ellswift_ours[4:] + peer1.v2_state.sent_garbage)
-        node0.bumpmocktime(3)
         # Ensure that the bytes sent after 4 bytes network magic are actually received.
         self.wait_until(lambda: node0.getpeerinfo()[-1]["bytesrecv"] > 4)
+        self.wait_until(lambda: node0.getpeerinfo()[-1]["bytessent"] > 0)
+        node0.bumpmocktime(3)
         with node0.assert_debug_log(['V2 handshake timeout peer=0']):
             node0.bumpmocktime(1)  # `InactivityCheck()` triggers now
             peer1.wait_for_disconnect(timeout=1)