Move HPACK fuzzing corpus generator to net/spdy

Merge internal change: 217702541

R=rch@chromium.org

Change-Id: I7f79cc85a57bce8e5c0f819ee83296b30c917320
Reviewed-on: https://chromium-review.googlesource.com/c/1287072
Commit-Queue: Victor Vasiliev <vasilvv@chromium.org>
Reviewed-by: Ryan Hamilton <rch@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#601217}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 802b8d0211b2703eaa521a5075bd0dba58cbe387
5 files changed