Bug 1015791 - Retrieve the constructor for the slot, rather than looking up |proto.constructor|, for JSFUN_GENERIC_NATIVE functions. r=luke

Note that the Array and TypedArray changes here are very ephemeral, because
we're about to convert these things to ClassSpec (which does this right
automatically) in the upcoming patches.
Bug 1015791 - Give Array a ClassSpec. r=luke
Bug 1015791 - Stop assuming that all TypedArray classes are initialized simultaneously. r=luke
Bug 1015791 - Clean up duplication in release-mode conditionality of *Array.prototype.move. r=luke
Bug 1015791 - Hoist TypedArray properties into a JSPropertySpec. r=luke
Bug 1015791 - Give TypedArray classes a ClassSpec. r=luke
Bug 1015791 - Break up the remainder of js_InitTypedArrayClasses. r=luke