layers: Move lock around add_object_create_info in core_validation
layers: Move lock around add_object_create_info in core_validation

Change-Id: I9b183e1231fecc7dce8db9899ee115c5e7a2be3e

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