Merge #2638: [QA] Fix intermittent mempool sync failures in sapling_w…

…allet_nullifiers

0f79bdc [QA] Fix intermittent mempool sync failures in sapling_wallet_nullifiers (random-zebra)

Pull request description:

  Still (somewhat frequent) mempool sync failures in this test, even after #2633.

  This is because `node1` might still be in IBD when he receives the first tx INV message, and, with #2611, nodes no longer send (non-block) getdata requests during initial sync.

ACKs for top commit:
  furszy:
    great catch, ACK 0f79bdc.
  Fuzzbawls:
    ACK 0f79bdc

Tree-SHA512: a3f3b81848893803ba04e93d605d7d6accb2b2a28c62a8d7dbd09ae5513111c917c46f1e30eccacdf9b6ac9f1caf06ff4383fd0071d55133f49e8798e68933d4

test/functional/sapling_wallet_nullifiers.py

@@ -22,6 +22,7 @@ def set_test_params(self):
 
     def run_test (self):
         self.nodes[0].generate(1) # activate Sapling
+        self.sync_all()
 
         # add shield addr to node 0
         myzaddr0 = self.nodes[0].getnewshieldaddress()
@@ -32,9 +33,7 @@ def run_test (self):
         recipients = []
         recipients.append({"address":myzaddr0, "amount":Decimal('10.0') - Decimal('1')}) # utxo amount less fee
 
-        txid = self.nodes[0].shieldsendmany(mytaddr, recipients)
-
-        self.sync_all()
+        self.nodes[0].shieldsendmany(mytaddr, recipients)
         self.nodes[0].generate(1)
         self.sync_all()