The API in the wasm module builder changed recently
(https://crrev.com/c/2390144). The fuzzer was still emitting code for
the old API.
This CL fixes this for primitive types, and adds a TODO to implement
heap types when needed.

R=ahaas@chromium.org
CC=manoskouk@chromium.org

Bug: chromium:1127717
Change-Id: I514b6e53d0492e5706a5b06d24026da13c3a2165
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2412176Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69921}