Vulkan: Non-zero memory initialization for all images This was only implemented for single-level, single-layer, single-sample color images. This change implements clear for all images. Additionally, the move to VMA broke the initialization of the staging buffer, so even for the supported case, the image was being initialized with uninitialized data. Bug: angleproject:4092 Bug: angleproject:4551 Change-Id: Ic2eee3f8454a93f1bcf3ca725afabcdc693047e1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2249376 Reviewed-by: Tim Van Patten <timvp@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>