The Fuchsia SDK will no longer include QEMU as part of the tarball.
QEMU will be downloaded separately from CIPD instead.

Fixes V8 roll failure: https://chromium-review.googlesource.com/1180602

Tested by verifying that
//build/config/fuchsia:blobstore_extended_qcow2 builds using the updated
Chromium build targets in //build/fuchsia/.

Change-Id: I01795aaf45dcdaa1a05481e4a72302c7aa387b3a
Reviewed-on: https://chromium-review.googlesource.com/1181688
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55235}