Some tests and testing infrastructure had to be changed because it
relied on nominal types.
Drive-by: Support function supertypes in wasm-module-builder.js.

Bug: v8:7748
Change-Id: Ife92431d1842ff9de91e296a50421aa48f02c0de
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3776197Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81862}