The spec wasn't clear (or I misunderstood). As per
(https://github.com/WebAssembly/bulk-memory-operations/issues/11),
zero-count table operations are also out of bounds.

R=mstarzinger@chromium.org
CC=binji@chromium.org
BUG=v8:7747

Change-Id: Iac689b93a040eb6eb06975bc2ba0facb85d24756
Reviewed-on: https://chromium-review.googlesource.com/c/1436022Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59121}