[js] optimize Lambda.indexOf for Arrays (closes #1242)

This change adds an optimizing filter for Js platform that transforms Lambda.indexOf(o, i) calls to o.indexOf(i) when o is known to be Array.

Also, it adds a "feature" that adds indexOf implementation if it's not available on runtime (for IE8).

Also because of above change, HxOverrides.remove was refactored to always use indexOf and require that feature.