The code did originally only handle the int32 case, but was then
extended to all wasm types in https://crrev.com/c/1965577. The comments
and variable names still mention the int32 type only though.
This CL fixes that.

R=ecmziegler@chromium.org

Bug: v8:10070
Change-Id: I3b1fa4047ee7ee9f283dce3758f6b8a39c964b22
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2017723
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65970}