Rename element_size_bytes() to value_kind_size(), and add
the uncompressed version: value_kind_full_size().

R=clemensb@chromium.org

Change-Id: I956142937fd1134ecbdaaa617c402ed8fff2cf17
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3568477Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79884}