This got lost in the 4.0 question bank work.
We are trying to phase out qtype_random, that is where the old
code and lang strings for describing random questions is, so
OK to add back a call to it. When we get better qbank filtering
we can replace this again.
Note, the asserts in the Behat were copied from my 3.11, checkout,
to really verify we are restoring the previous behaviour.
2e1a632302