違いを調べてみたが、ほとんど一緒で違いがわからぬ
abort_on_exception
Returns the status of the global “abort on exception” condition.
When set to true, if any thread is aborted by an exception, the raised exception will be re-raised in the main thread.
report_on_exception
Returns the status of the global “report on exception” condition.
When set to true, all threads will report the exception if an exception is raised in any thread.
ruby-lang:Thread
https://ruby-doc.org/core-2.4.0/Thread.html