Bug 992267: Introduce the IsSimdAvailable testing function; r=luke

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extra : rebase_source : 65975807c240817b7cc7dfb8bfca59f5d8f6d6a0
Bug 992267: Ensure stack alignment requirements for asm.js code; r=bbouvier

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extra : rebase_source : 5d5b45fc4418bf8898cdf0a735386140ebc8b230
Bug 992267: Odin basic SIMD support; r=luke
* * *
Bug 992267: Add SIMD globals support to Odin; r=luke

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extra : rebase_source : 7a10c51e0e9be701b91e462caff2701a6c52c258