Bug 911043 (part 1) - Move the "inject JS:: names into js::" block into its own file, to reduce dependencies on jsapi.h.  r=luke.

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extra : rebase_source : 2250064bdd316ffeb8126da749bdf94ab9da4418
Bug 911043 (part 2) - Remove unnecessary jsapi.h includes in SpiderMonkey.  r=luke.

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extra : rebase_source : 2320e364bb9efb59283a572e100185702ef494da