- Adds embedder callback to notify fully tiered compilation is finished,
  returning a WasmCompiledModule for serialization.
- Adds function to pass previously compiled bytes into WASM streaming
  compilation, for deserialization.
- Plumbs this API through StreamingDecoder.

Bug: chromium:719172
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Ibe376f3a8ccfa90fda730ef4ff6628a1532da45c
Reviewed-on: https://chromium-review.googlesource.com/c/1252884Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56617}