scripted-diff: test: Rename send_message to send_without_ping

send_message only drops the bytes in a buffer and a sync is needed to
avoid intermittent test issues. Change the name of the method to make
this more apparent during review.

-BEGIN VERIFY SCRIPT-
 sed -i 's/send_message(/send_without_ping(/g' $( git grep -l 'send_message(' )
-END VERIFY SCRIPT-

test/functional/p2p_initial_headers_sync.py

@@ -45,7 +45,7 @@ class HeadersSyncTest(BitcoinTestFramework):
         # An empty reply will clear the outstanding getheaders request,
         # allowing additional getheaders requests to be sent to this peer in
         # the future.
-        peer1.send_message(msg_headers())
+        peer1.send_without_ping(msg_headers())
 
         self.log.info("Connecting two more peers to node0")
         # Connect 2 more peers; they should not receive a getheaders yet
@@ -66,7 +66,7 @@ class HeadersSyncTest(BitcoinTestFramework):
 
         self.log.info("Check that peer1 receives a getheaders in response")
         peer1.wait_for_getheaders(block_hash=best_block_hash)
-        peer1.send_message(msg_headers()) # Send empty response, see above
+        peer1.send_without_ping(msg_headers()) # Send empty response, see above
 
         self.log.info("Check that exactly 1 of {peer2, peer3} received a getheaders in response")
         count = 0
@@ -76,7 +76,7 @@ class HeadersSyncTest(BitcoinTestFramework):
                 if "getheaders" in p.last_message:
                     count += 1
                     peer_receiving_getheaders = p
-                    p.send_message(msg_headers()) # Send empty response, see above
+                    p.send_without_ping(msg_headers()) # Send empty response, see above
 
         assert_equal(count, 1)