Re #8613. Add a test that exposes the bug.
Re #8613. Remove code that bails out early if no events in a bank.

We need the bank name to be added to the list even if it's empty as it's
checked for if the BankNames property has been set. There's already a check
that means that no LoadBankFromDiskTask is created for the bank if it's
empty (the original justification for adding this code in commit [36540217]).

I don't think this change has much other effect, but I'll be relying
heavily on the tests to confirm that given the horrific complexity of
the file.
Merge remote-tracking branch 'origin/feature/8613_loadeventnexus_empty_bank_failure'