Load ncs_codes for tests using pg_restore instead of a bunch of YAML-derived INSERTs

For running a single low-complexity focused spec, this change shows an 80% reduction in the time spent in RSpec — it decreases the time from 2.5s to about 0.5s. The wall-clock reduction is less impressive (20s -> 18s) because it doesn't address the high overhead of loading Cases' bundle.

But 2s isn't nothing.