Merge #19887: test: Fix flaky wallet_basic test

56b018c test: Fix flaky wallet_basic test (Fabian Jahr)

Pull request description:

  Fixes #19853

  I investigated the issue in #19876 and I still intend to fix the underlying issue of a race when using wallet RPCs right after starting a node in that PR. However, since that is a bit more complicated than I initially thought it makes sense to merge the fix of the test so the intermittent test failures stop. This fix in the test is going to be needed, either way, #19876 will only provide an error where before it was reporting a false balance.

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Tree-SHA512: 52bb2388a3e77aa20d26ab0fd45796bc1781483b1cffe49cbb44e2488a72e76998edfb1198495373f9c6fd2ec26064d4176bd1a64dd59806622d5e50a4f4e870

Author: MarcoFalke

test/functional/wallet_basic.py

@@ -596,6 +596,9 @@ def run_test(self):
         # wait until the wallet has submitted all transactions to the mempool
         self.wait_until(lambda: len(self.nodes[0].getrawmempool()) == chainlimit * 2)
 
+        # Prevent potential race condition when calling wallet RPCs right after restart
+        self.nodes[0].syncwithvalidationinterfacequeue()
+
         node0_balance = self.nodes[0].getbalance()
         # With walletrejectlongchains we will not create the tx and store it in our wallet.
         assert_raises_rpc_error(-6, "Transaction has too long of a mempool chain", self.nodes[0].sendtoaddress, sending_addr, node0_balance - Decimal('0.01'))