Revert #6192. It was causing a JS error on devstack.

TNL-1070
@andy-armstrong As far as I can tell, just having this line in the file causes combinedopenended's compiled version of the file to appear with a filename alphabetically before xmodule.js' file. Even when this line is never executed. So I think it is just bad luck that the change exposed the lurking bug that we do not enforce ordering between the various common JS files.

I'm not sure how to add ordering, given that the filenames end up being completely munged. Perhaps we can prevent xmodules.js from going through the renaming process that gives it a munged name (since it is no longer a coffee file, it doesn't need the compilation step), and then we can explicitly load that file before the other ones in pipeline_js.