Fix linux build

Linux is case sensitive, and [Makefile.in](https://github.com/ricardoquesada/Spidermonkey/blob/master/js/src/Makefile.in#L597) searchs for ```Array.js```, but the file is called ```array.js``` upstream.
This PR simply adds a symlink from ```Array.js``` to ```array.js``` so it will not happen again.