This CL removes wasm-js.cc from compilation if
v8_enable_webassembly=false. In order to do so, an alternative
implementation of {v8::WasmStreaming} has to be provided, because the
public API should stay unchanged. The only path to obtain a
{v8::WasmStreaming} object is via {v8::WasmStreaming::Unpack}, which
will always fail if WebAssembly is not supported. Hence all methods in
{WasmStreamingImpl} are unreachable.

As a drive-by, this CL removes all includes from src/wasm in src/init
(bootstrapper.cc would have been done anyway, and v8.cc is just a few
 changes).

R=jkummerow@chromium.org

Bug: v8:11238
Change-Id: Ic0638eb5cda91ec29c1c07ef400bc670c91630fb
Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2737300Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73234}