layers: Exclude index buffer from CBSTATUS_ALL mask
layers: Exclude index buffer from CBSTATUS_ALL mask

The CBSTATUS_ALL mask is set to default all dynamic state to static in the
PSO. The index buffer doesn't fall under the other dynamic state umbrella
so excluding it from the CBSTATUS_ALL mask.

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools