test: failure in interface_rest.py #26440

https://cirrus-ci.com/task/4924805592907776?logs=functional_tests#L2972

 test  2022-11-01T13:38:30.771000Z TestFramework (ERROR): Assertion failed 
                                   Traceback (most recent call last):
                                     File "C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\test\functional\test_framework\test_framework.py", line 133, in main
                                       self.run_test()
                                     File "C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\test\functional\interface_rest.py", line 103, in run_test
                                       self.sync_all()
                                     File "C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\test\functional\test_framework\test_framework.py", line 715, in sync_all
                                       self.sync_mempools(nodes)
                                     File "C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\test\functional\test_framework\test_framework.py", line 708, in sync_mempools
                                       raise AssertionError("Mempool sync timed out after {}s:{}".format(
                                   AssertionError: Mempool sync timed out after 480s:
                                     {'cbd1d27c4d06b4dfd479c34aef4b57d3be14dfc20ccc74f2699fde370f17d1d3'}
                                     set()
 test  2022-11-01T13:38:30.771000Z TestFramework (DEBUG): Closing down network thread 

I think this issue is related to interface_rest.py, isn't it? https://cirrus-ci.com/task/4924805592907776?logs=functional_tests#L3372

https://cirrus-ci.com/task/6319943846199296 https://cirrus-ci.com/task/5934934255206400

I built an archive of the CI log failures in order to (try to) track these intermittent failures if you're interested: https://github.com/aureleoules/bitcoin-core-ci-logs Not sure how useful this is so far.

The issue in https://cirrus-ci.com/task/4924805592907776?logs=functional_tests#L2972 seems to be that the nodes aren't connected yet at the time the tx is added (and, therefore, the tx is not propagated and mempool sync fails):

 test  2022-11-01T13:30:30.622000Z TestFramework (INFO): Broadcast test transaction and sync nodes
(...)
 node0 2022-11-01T13:30:30.648282Z [C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\src\validationinterface.cpp:211] [operator ()] [validation] TransactionAddedToMempool: txid=cbd1d27c4d06b4dfd479c34aef4b57d3be14dfc20ccc74f2699fde370f17d1d3 wtxid=a0693a39de8466f542ef40b30e3fe1a391b2863927c5a28838ed65a3f3e84177 
(...)
 node0 2022-11-01T13:30:30.704227Z [C:\Users\ContainerAdministrator\AppData\Local\Temp\cirrus-ci-build\src\net_processing.cpp:3149] [ProcessMessage] [net] received: verack (0 bytes) peer=0 

I don't understand how this is possible, setup() should wait for the verack, so that run_test() is not called before the two nodes are successfully connected.

Closing as presumed duplicate of #26852 (same underlying cause)