[NS] Tests : don't expect a score in NF#acceptRequest

The score argument is going away, so there no longer
is a need to test it. It's never been used by anybody
and is actually a problem going forward.

Since removing the argument requires a small re-arch
of the testing tool anyway, rebuild expecting requests
on top of TrackRecord. This simplifies the test a
great deal, as well as (as observed in running the
tests) makes the test faster.

Test: this
Change-Id: If03b9e64f14ac8ffa5398b964939a9a45a74b28d