Remove all usages of SPVC from the code and update the fuzzers. Some
of the include paths and deps came transitively from spvc, so needed
to update build rules.
This patch does NOT remove the flags related to spvc usage, they are
just no-ops as the moment. After this patch lands I will remove the
usage of those flags from the bots, then remove the flags.
BUG=dawn:521
Change-Id: I0d7c3e28f79354c78f00c48b6a383b823094a069
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/27900
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>