For some input types containing -0 but not +0, the result type of
NumberMin and NumberMax would unnecessarily include +0. However, for
some larger inputs, the result type would not include the spurious +0,
thus breaking monotonicity.

The CL fixes this and addresses a TODO as well.

Bug: chromium:1063661
Change-Id: Icd56d6102fbea12a2d96aa063a803b1052c714b8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2116199
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66854}