Add support for the i8 and i16 packed types.
Because i8 and i16 do not exist as value types
we need an i32 to instantiate a packed field.

Bug: v8:11954
Change-Id: Ib311fee537c4c9e4aed0ac366172b9b5fb1ee88e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3210267
Commit-Queue: Maria Tîmbur <mtimbur@google.com>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77288}