Grouping a couple of small, non-functional fixes:

- add a comment to GetStackParameterDelta
- small typo fixes to a couple of places I saw while reading related
code

Bug: v8:11879
Change-Id: I8566c9778fd6268b08ea3aefbdaa84ef894bcd35
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2997922Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75490}