This patch changes the way StructuredSerializeInternal() serialize
strings by storing four bytes into a 32-bit entry, instead of one code
point per 32-bit entry.
StructuredDeserialize() has also been changed to deserialize strings by
the same ruleset.
This implementation only works for cloning Numbers, and does not try to
do all the spec steps for structured serialize and deserialize.
Co-Authored-By: Andrew Kaster <akaster@serenityos.org>