This renames more fields holding "ValueKind" or methods operating on
"ValueKind" to contain "kind" instead of "type".
It also renames "is_reference_type" to "is_reference" on both ValueType
and ValueKind, as the "_type" prefix is kind of implicit from the
argument.

R=manoskouk@chromium.org, jgruber@chromium.org

Bug: v8:11477
Change-Id: I7809f1af6e983aebca96e03fe1fbc6ccaa22db72
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718063
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73070}