Bug 878399: Preparatory cleanups; r=luke

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extra : rebase_source : febbb6a64aa0790641c5e0efb7103deac4412caa
Bug 878399: Implement toSource / toString for asm.js modules; r=luke

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extra : rebase_source : 327cb71b2731a1a2fe6a0176fffc7aa4ba949870
Bug 878399: Implement toSource / toString for asm.js modules lambda; r=luke
Bug 878399: Implement toSource / toString for asm.js functions; r=luke