Also block sending "type" as part of the ObjectPreview, but only send
the "value" property. The front-end will be updated to display
WasmValueObject's similar to what we do for wrapper objects (i.e.
StringWrapper and the like). The matching front-end change is still
pending.

Also refactor the WasmValueObject to have dedicated constructors for
the individual types (i32, i64, f32, f64, externref and v128). This
way we can just reuse the existing logic in descriptionForObject()
and we also don't need to store the "type" on the object itself (not
really performance sensitive, but fewer moving parts / things that
can go wrong).

This also addresses the crash in https://crbug.com/1166077#c16 since
the WasmValueObject instances now have a proper JSFunction in their
maps' constructor_or_backpointer slot and are thus able to locate
their creation context. Note that this doesn't generally address
https://crbug.com/1166077 itself, but only the WasmValueObject case.

Screenshot: https://imgur.com/kbd3bix.png
Bug: chromium:1170282, chromium:1071432
Bug: chromium:1159402, chromium:1166077
Change-Id: Iae649cad155efd774cfb1f4eea8cf406e413c03a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2692574Reviewed-by: Philip Pfaffe <pfaffe@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72736}