Adjust JRuby in CI for greening
Adjust JRuby in CI for greening

JRuby 9.2.9 has a bug that causes failures on Java 11, so I'm
moving it to allowed failures for now. The bug is fixed in JRuby
9.2.10 (head) and we would like jruby-head to always be green, so
I have removed it from allowed failures.

The --dev flag should help reduce startup time for all JRuby
processes.

* Remove jruby-head from allowed failures
* Temporarily move JRuby 9.2.9 on Java 11 to allowed failures
* Add --dev to speed up JRuby launches

lucasallan/concurrent-ruby,lucasallan/concurrent-ruby,lucasallan/concurrent-ruby,lucasallan/concurrent-ruby,lucasallan/concurrent-ruby