Merge #19893: test: Remove or explain syncwithvalidationinterfacequeue

fa6af312277bb1b7e57d9b764d411c5b0873829f test: Document why syncwithvalidationinterfacequeue is needed in tests (MarcoFalke)
fa135a13b8ddaa117bd090ec43a3eab3a95755c1 Revert "test: Add missing sync_all to wallet_balance test" (MarcoFalke)

Pull request description:

  syncwithvalidationinterfacequeue is a hidden test-only RPC, so it should not be used when it is not needed. Thus, either remove it or explain why it is needed.

ACKs for top commit:
  fjahr:
    Code review ACK fa6af312277bb1b7e57d9b764d411c5b0873829f

Tree-SHA512: de30db4ab521184091ee5beeab02989138cf7cf05088f766a2fb106151b239310b63d5380cb79e2a072f72c5ae9513aecae8eb9c1c7be713771585c3cb04d63a

test/functional/wallet_balance.py

@@ -204,8 +204,6 @@ class WalletTest(BitcoinTestFramework):
         self.log.info('Put txs back into mempool of node 1 (not node 0)')
         self.nodes[0].invalidateblock(block_reorg)
         self.nodes[1].invalidateblock(block_reorg)
-        self.sync_blocks()
-        self.nodes[0].syncwithvalidationinterfacequeue()
         assert_equal(self.nodes[0].getbalance(minconf=0), 0)  # wallet txs not in the mempool are untrusted
         self.nodes[0].generatetoaddress(1, ADDRESS_WATCHONLY)
         assert_equal(self.nodes[0].getbalance(minconf=0), 0)  # wallet txs not in the mempool are untrusted

test/functional/wallet_importmulti.py

@@ -63,7 +63,7 @@ class ImportMultiTest(BitcoinTestFramework):
         self.nodes[0].generate(1)
         self.nodes[1].generate(1)
         timestamp = self.nodes[1].getblock(self.nodes[1].getbestblockhash())['mediantime']
-        self.nodes[1].syncwithvalidationinterfacequeue()
+        self.nodes[1].syncwithvalidationinterfacequeue()  # Sync the timestamp to the wallet, so that importmulti works
 
         node0_address1 = self.nodes[0].getaddressinfo(self.nodes[0].getnewaddress())
 

test/functional/wallet_resendwallettransactions.py

@@ -52,6 +52,7 @@ class ResendWalletTransactionsTest(BitcoinTestFramework):
         block.solve()
         node.submitblock(ToHex(block))
 
+        # Set correct m_best_block_time, which is used in ResendWalletTransactions
         node.syncwithvalidationinterfacequeue()
 
         # Transaction should not be rebroadcast within first 12 hours