To serialize an `UnknownArrayHandle`, a pair of lists were created to
specify all possible value and storage types. These were then used in an
`UncertainArrayHandle::CastAndCall`, which would in turn take the cross
of these two lists. This resulted in a _really_ long list that gave
compilers trouble.
Reduce the size of the list by separating out value types by the number
of components, which can be easily deduced.
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