Add a global debug method
Refactor spec suite runner
minitest_spec needs to test Minitest 5
minitest_test tests both 4 and 5
Don't need the minitest_4 suite as we can re-use the minitest one
Fix the run_full_test_suite script so it properly runs the minitest_4 suite
Add JRuby to the list of Rubies in the run_full_test_suite script