translator: Avoid divide-by-zero in error case. In some code path found by a fuzzer, we would have a zero sized array, which would trigger a zero divide. I was unable to extract the failing shader from the fuzzer case trivially. BUG=chromium:653274 Change-Id: Ia2558ae828fa73615c901fd1cda9ddaa3a72f1a9 Reviewed-on: https://chromium-review.googlesource.com/394238 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>