Only support empty exceptions for now. Unpacking i32s, and eventually
arbitrary types, will be done in separate CLs.

R=clemensb@chromium.org

Bug: v8:11453
Change-Id: Ic3233e0bbdaad8b710cd836be9aef647d3131c9d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2739590
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73402}