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/feature_assumeutxo.py

@@ -309,7 +309,7 @@ class AssumeutxoTest(BitcoinTestFramework):
         msg = msg_headers()
         for block_num in range(1, miner.getblockcount()+1):
             msg.headers.append(from_hex(CBlockHeader(), miner.getblockheader(miner.getblockhash(block_num), verbose=False)))
-        headers_provider_conn.send_message(msg)
+        headers_provider_conn.send_without_ping(msg)
 
         # Ensure headers arrived
         default_value = {'status': ''}  # No status