Serialization of WasmModuleObject was our first implementation for
postMessage, and was used for IndexedDB. IndexedDB support is removed
since a long time, and postMessage works by just messaging an identifier
and reusing the underlying NativeModule when receiving this.
Thus the logic to serialize the actual code is unused, and thus should
be removed together with all tests.

R=ahaas@chromium.org

Bug: v8:10146
Change-Id: I599296736dabd486c45ced2b6e5996e490fa40c8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2013110Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65922}