Fix failing TEST (active_transactions, fifo)

[gr0vity-dev]

This testcase manually pushes two blocks to the election scheduler.
However the backlog population sometimes also pushes the block to the election scheduler resulting in it being dropped twice.
--> The solution is to disable the backlog population for this testcase

After this change I ran the testcase 100k times and saw it failing only once. (Compared to ~1 in 1000 before)

The stats indicate that an election can still get activated by priority scheduler:
type: election_scheduler detail: insert_priority dir: in value: 1

The only other place I found that runs a priority scheduler is here in nano::active_transactions::activate_successors

[dsiganos]

Nice one! This test case been bugging me! Detailed tracing looks extremely useful!

[dsiganos]

nano::active_transactions::activate_successors is called from
nano::active_transactions::handle_final_votes_confirmation which is called from
nano::active_transactions::block_cemented_callback which is called for every cemented block.

So it appears that every newly cemented block triggers an election for its successor, if we are past the bootstrap_weight_max_blocks point.

[dsiganos]

Try setting node.ledger.bootstrap_weight_max_blocks to a large number so that that activate_successors is not triggered (e.g. 100).

[gr0vity-dev]

Nice one! This test case been bugging me! Detailed tracing looks extremely useful!

This is simply printing the statsto cout. Here is a .patch file to apply those for debugging purposes.
stats_to_cout.patch