Vulkan: Fix alignment issues with SecondaryCommandBuffer This solves undefined behaviour on 64-bit systems. This inflates the size of a few commands, but most commands either already did align to 8 bytes or could be aligned to 8 bytes with a few tweaks. Bug: angleproject:7852 Change-Id: Ie61976d5bf8df7790acd95c0e15d4c79402622a1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5288636 Reviewed-by: Charlie Lao <cclao@google.com> Reviewed-by: Yuxin Hu <yuxinhu@google.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>