Previously we had introduced a special `v8::internal::WasmValue` type
which we used to expose Wasm values to the Scope view in Chromium
DevTools. The problem however is that these values cannot be exposed to
JavaScript (and in particular not to Debug Evaluate), which means that
particularly for v128 and i64 we have inconsistent representations
across the various parts of DevTools.

This change removes the `wasm` type from the RemoteObject and all the
adjacent logic, and paves the way for a uniform representation of Wasm
values throughout DevTools. For i64 we will simply use BigInt
consistently everywhere, and for i32, f32 and f64 we'll just use Number.
For externref we will represent the values as-is directly. For v128
values we currently use a Uint8Array, but will introduce a dedicated
WasmSimd128 class in a follow-up CL.

Bug: chromium:1071432
Fixed: chromium:1159402
Change-Id: I0671e5736c9c27d7ca376e23ed74f16d36e03c80
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2614428Reviewed-by: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71962}