graphics/vulkan-validation-layers: disable assertions as recommended
$ vkcube-xcb --validate
WARNING : PERFORMANCE - Message Id Number: 648835635 | Message Id Name: UNASSIGNED-khronos-Validation-debug-build-warning-message
Validation Performance Warning: [ UNASSIGNED-khronos-Validation-debug-build-warning-message ] Object 0: handle = 0x800a50100, type = VK_OBJECT_TYPE_INSTANCE; | MessageID = 0x26ac7233 | VALIDATION LAYERS WARNING: Using debug builds of the validation layers *will* adversely affect performance.
Objects - 1
Object[0] - VK_OBJECT_TYPE_INSTANCE, Handle 0x800a50100[...]