We introduce {ConstantExpression}, which represents the most frequent
constant expression types directly, and falls back to a {WireBytesRef}
for the rest. During module decoding, we decode the most common
expressions separately and store them as {ConstantExpression}, so we do
not have to decode them again during module instantiation.

Bug: chromium:1284557
Change-Id: Ie411bbe9811d0d9f6e750ba202bb0ccff801dfee
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3378347Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78576}