Add a test to generate a "R" notification by:
- sending a tx on node0 while the nodes are disconnected
- verifying that this transaction is added to node0's mempool
- generating a conflicting tx on node1
- mining the conflicting tx into a block on node1
- reconnecting the nodes
- checking that the first tx is rejected on node0
Also add `noban` permission to all nodes to avoid the tx relay delays, because there are a lot of calls to `sync_all` and this diff adds more of them. This reduces the test run time from 45s to 14s.
This replaces the RBF tests that were in [[https://github.com/bitcoin/bitcoin/pull/19572 | core#19572]] backported in D10306.