Bundle: Allows TypeScript in JS bundles. (#1347)

For details, please visit #1347

Now lets hope I don't break everyone's life :smiley: 


@scabana, this is actually wrong and quite unnecessary. We don't know for a fact that the generated JS fie for that TS code would reside in same folder! I think we should consider this as an invalid case. So user must provide JS files in JS bundles and TS files in TS bundles.

I am making couple of fixes for bundle, which includes removing this condition.

Thoughts?