This is the first CL to refactor WebAssembly.instantiateStreaming to
make it spec compliant again. The design doc where the whole change is
discussed is available in the tracking bug. The tracking bug also
references prototype implementations of the whole change, which includes
the changes in this CL.

Tests for the new API functions will be added with the second V8 CL
which adds the implementation of the API functions.

R=ulan@chromium.org

Bug: chromium:860637
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Ia1048b7ca0291c824ef4212ebde2c6054e102069
Reviewed-on: https://chromium-review.googlesource.com/1127667Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54393}