Demonstrate the issue with --seed=50992

Which is not related to my other branch in any way
Reset I18n.backend to make locale test order-independent

Previously it would fail tests when ran with a certain seed value,
due to I18n.backend containing too many useable translations.

For this test to run with certainty the backend should be re-initialized
to an empty one at the beginning.
Merge branch 'test-ordering-issue' into deep-merges-with-chain-lookup