Add more EUnit fudge time to generic_qc_fsm:qc_test_()
Another round of trying to eliminate PULSE nondeterminism.

* PULSE side-effect for all bitcask_nifs functions, !@#$!.  The
function-by-function declaration is too specific and thus too brittle.
Every time a new NIF is added or an existing NIF arity is changed,
everyone (myself included) forgets to change rebar.config.script.
Instead, we'll use a blanket wildcard statement, and for the few
non-NIF functions in bitcask_nifs.erl, they'll get instrumented too.

* Move make_merge_file() from bitcask_pulse.erl -> bitcask.erl,
because bitcask_pulse has an explicit `pulse_no_side_effect`
directive for file:'_' calls.