Reconsider Sign abstract operation #1593
Description
From the review of #1585: maybe we should consider removing Sign after all. As far as I can tell, it never actually operates on Number values in the Temporal spec text, so the whole justification for adding it and using it in Math.sign() when merging into 262 doesn't exist.
Could be replaced with language like "Let sign be the mathematical value whose sign is the sign of value and whose magnitude is 1," while making sure to account for the 0 case separately.