[Runtime] Add a cache to the ObjectRuntime for caching runtime objects.

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Proposal Details

Add a cache to the ObjectRuntime for caching runtime objects.

Once the runtime objects are read from cache, there is no need to deserialize object from bytes, thus improving the speed of transaction execution.

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There is a problem that when calling RuntimeObject::into_change, the value of RuntimeObject is moved, but we need to put it in the cache, so we need to implement a reference version of into_change. This requires implementing a reference version of GlobalValue::into_effect in the move repo.

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There are two more issue we need consider:

1. ObjectRuntime::load_object returns &mut RuntimeObject. If the cache is added, the reference can be returned from two sources: ObjectRuntime itself and the cache. This may make a lot of the interface to be changed.
2. As ObjectRuntime::load_object is recursive, it may result in more than one mut reference to the cache.

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Make this issue TBD