Merge bitcoin#19887: test: Fix flaky wallet_basic test

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

Pull request description:

  Fixes bitcoin#19853

  I investigated the issue in bitcoin#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, bitcoin#19876 will only provide an error where before it was reporting a false balance.

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Tree-SHA512: 52bb2388a3e77aa20d26ab0fd45796bc1781483b1cffe49cbb44e2488a72e76998edfb1198495373f9c6fd2ec26064d4176bd1a64dd59806622d5e50a4f4e870

test/functional/wallet_basic.py

@@ -487,6 +487,9 @@ def run_test(self):
             timeout -= 0.5
         assert_equal(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(-4, "Transaction has too long of a mempool chain", self.nodes[0].sendtoaddress, sending_addr, node0_balance - Decimal('0.01'))