Bug 900669 - convert some more ARM-only void* uses into ImmPtr (r=mjrosenb)

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extra : rebase_source : 8aa8548cece906325de356656e37af5812057c8d
Bug 900669 - OdinMonkey: avoid all uses of ImmPtr/AbsoluteAddress from asm.js code (r=bbouvier,mjrosenb,sr=jandem)