Translator: Fix init of inactive output variables Bug: chromium:398401939 Change-Id: I0df494b945b8d0e805a62cf7645d06bf233f36ca Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6438495 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>