Enable tests for Julia 0.3.X

It was mentioned in PR #5842 that Julia's testsuite fails under nixpkgs.

This PR enables the testsuite for Julia 0.3.X to demonstrate that it
works.

Since Julia is numerical software, I think it is a great idea to
merge this current PR so that Julia will always be tested in the
future.

I was unable to get the tests to pass on the 0.2.X branch.  However,
this branch is dead (its latest commit was Aug 8) and will receive
no more releases.