Fix syntax for 1.9.3, turn off tests that fail on JRuby, use RbConfig.ruby instead of "ruby"

* Was using keywords, that doesn't work on 1.9.3
* Spent couple of hours trying to figure out how to execute a fucking process and get an exit status on JRuby. No dice. Just turn those tests off when we are on JRuby.
* Found RbConfig.ruby, which is pretty cool, means I don't have to hope you have "ruby" in the path.