Of course there is no ISO standard for Julia (think about it for a minute… the language is still being developed very rapidly).
Also note that it is an extremely costly and long process to come up with such a standard, and to keep it updated later on. Moreover, even a lot of careful attention will not eliminate all corner cases and ambiguities, and then people can keep arguing about what the standard means, and supplement it with divergent intepretations.
If you are interested in this, Kent Pitman tells the story for Common Lisp here: http://www.nhplace.com/kent/Papers/cl-untold-story.html In particular, many people say that for CL having a standard had the insalutary effect of just freezing the language, with the understanding that nothing will ever change from that point onwards because no one will invest a ton of money for a new standardization process.
I don’t think it would have any benefit for Julia, but it would definitely work for taking up time for a lot of otherwise productive core devs, instead of improving the language.