Vulkan: getCommandBufferOneOff could reuse if serials are equal When one off commands serial is equal to last completed serial, it means completed. We should reuse command buffer instead of allocate a new one. Bug: b/259148812 Change-Id: Ibc006a93e1ee775a436396a0d35cf4ab2b363940 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4023097 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Yuxin Hu <yuxinhu@google.com> Commit-Queue: Charlie Lao <cclao@google.com>