Vulkan: Fix UBSAN error in CommandBatch CommandBatch doesn't initialize all fields, causing UBSAN errors in the move constructor. Bug: chromium:1261861 Change-Id: I46b963a415ccc08d3d9db40de98d1968eea311e8 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3241544 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>