Pull request description:
small improvements to clarify logic in the functional tests
1. have test logic in `rpc_net.py` match run order of the test
2. remove `connect_nodes` calls that are redundant with the automatic test setup executed by the test framework
Noticed when I was trying to debug a test for #19725. Small changes but imo very helpful, because they initially confused me.
Backport of core#19877