perf(continuations): Consider additional preinitialized segment

[Nashtare]

As mentioned in #466 description, once this lands we can add another segment to the preinitialized list basically for free. As such, we should consider if there is any outstanding segment in context 0 that would benefit from this approach.
I recall some time ago that we were considering either GlobalMetadata of the TxnFields ones, though we'd probably need to do preliminary analysis before settling on which one to go with.