Adds support to webassembly and enables it by default.
Adds wee8 target.

We can compile without wasm with:
`bazel build :d8 --no//:v8_enable_webassembly`

Bug: v8:11234
Change-Id: I90b11eb71aed808005b66e40e37894616d8b1658
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2960803
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75200}