Bug 1051860: Optimize SimdValueX4 codegen for float32x4 with unpcklps; r=sunfish

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extra : rebase_source : 30cec4448afa60e5be2a8e12f01daf95fffc94e3
Bug 1051860: Optimize SimdValueX4 codegen for int32x4 when SSE4.1 is available; r=sunfish

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extra : rebase_source : 3feb3d19834f6c356bb114ee8b19a283467dff34