Just prior to this commit, test_fork_conflict and test_fork_noconflict were essentially identical copies.
The only diff was that test_fork_conflict set the global blockchain.blockchains,
but this was not even affecting its behaviour anymore.
Originally when this test was added, we had the concept of chain fork conflicting with each other:
we could not handle three-way chain-splits. As in, there could only be a single fork forking away
from the main chain at any given height.
see 7221fb3231
However, this restriction was removed and generalised later:
141ff99580
After which the "test_fork_conflict" test did not make sense anymore.
9016c36df0