Because of ordering issues we didn't set the wire bytes on the
{NativeModule} during {OnFinishedStream}. We then failed during
instantiation when trying to read the import names from the wire bytes.

This CL fixes this locally without much code churn. I plan to clean up
the interaction between {AsyncCompileJob} and {AsyncStreamingProcessor}
in a follow-up CL.

R=ahaas@chromium.org

Bug: chromium:898310
Change-Id: I06337a04ba380f87b803f325323208298d363f41
Reviewed-on: https://chromium-review.googlesource.com/c/1296467Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56938}