revert verbose test code output

[depial]

The output for failures for concept exercises now matches the verbosity of those for practice exercises. This makes the extra verbose test code output for concept exercises redundant. This reverts the changes made to treat concept exercises differently to practice exercises.

The redundant information can be seen in the example below, with CODE RUN and TEST FAILURE both returning the same information. This reversion would bring the output in line with practice exercises by limiting the amount of information in the CODE RUN box to just the code run: @test can_free_prisoner(state[1:4]...) == state[5]