unstable:Thread#kill killing dying running does nothing
unstable(sleep status does not propagate in fibers properly):Thread#kill kills the entire thread when a fiber is active
unstable(JRuby does run ensures because they are JVM finally sections, so this only passes randomly due to racing):Thread#kill kills other fibers of that thread without running their ensure clauses
windows:Thread#kill kills other fibers of that thread without running their ensure clauses
