Translator: Fix SimplifyLoopConditions producing dead code This causes the tree to fail validation. Dead code could be generated if the loop body ended in a branch. In such a case, no additional instructions are added to the transformed loop body after the original body. Bug: chromium:1300782 Change-Id: I4ec46c170ab5a45fa9b9b73d4e2b62c9c4fa24a3 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3539442 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>