Auto merge of #397 - Xanewok:typed-arrays-stack-heap-variants, r=jdm
Add TypedArray API using Heap-wrapped objects
Needed for https://github.com/servo/servo/pull/20267.
This changes TypedArray wrapper type to only contain typed array-related logic and not handle rooting, and introduces 2 different possible storage options for wrapped objects
- `*mut JSObject`, can be rooted on stack (e.g. using CustomAutoRooter)
- `Box<Heap<*mut JSObject>>`, can be rooted on heap with `JSTraceable` trait (implemented on Servo side)
Since the API changes are breaking, I bumped minor version so that Servo will not break when updating.
r? @jdm
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