qa: Fix race condition in sendheaders.py

Github-Pull: #11538
Rebased-From: 6d51eaefe9

test/functional/replace-by-fee.py

@@ -72,12 +72,14 @@ class ReplaceByFeeTest(BitcoinTestFramework):
                            ["-mempoolreplacement=0"]]
 
     def run_test(self):
-        # Leave IBD and ensure nodes are synced
+        # Leave IBD
         self.nodes[0].generate(1)
-        self.sync_all()
 
         make_utxo(self.nodes[0], 1*COIN)
 
+        # Ensure nodes are synced
+        self.sync_all()
+
         self.log.info("Running test simple doublespend...")
         self.test_simple_doublespend()
 

test/functional/sendheaders.py

@@ -225,6 +225,10 @@ class SendHeadersTest(BitcoinTestFramework):
         inv_node.wait_for_verack()
         test_node.wait_for_verack()
 
+        # Ensure verack's have been processed by our peer
+        inv_node.sync_with_ping()
+        test_node.sync_with_ping()
+
         tip = int(self.nodes[0].getbestblockhash(), 16)
 
         # PART 1