add test for object comparability

[bashbaug]

See https://github.com/KhronosGroup/OpenCL-Docs/issues/797.

We should add basic testing for object comparability, to ensure that object handles compare equal when they are queried from child objects.

[bashbaug]

A good initial step towards resolving this issue would be a test plan documenting what will be tested.

[shajder]

@bashbaug @Snektron in most cases such comparability is already performed, I went through spec and CTS. It looks like the problem is mostly related to querying command queues, I found multiple similar comments:

    // We can not check if this is the right queue because this is an opaque
    // object.

I am assuming this is no longer correct statement and we should compare queried command queues just like in cases of command_buffer_get_command_buffer_info.cpp. Below my comments for completed and missing cases:

1. clGetCommandBufferInfoKHR with params:

• CL_COMMAND_BUFFER_QUEUES_KHR - done,
• CL_COMMAND_BUFFER_CONTEXT_KHR - done

2. clGetCommandQueueInfo with params:

• CL_QUEUE_CONTEXT - done,
• CL_QUEUE_DEVICE - done,
• CL_QUEUE_DEVICE_DEFAULT - comparison missing

3. clGetContextInfo with param:

• CL_CONTEXT_DEVICES (including multi-device case) - comparison missing

4. clGetDeviceInfo with param:

• CL_DEVICE_PLATFORM - comparison missing

5. clGetGLContextInfoKHR with params:

• CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR - comparison missing,
• CL_DEVICES_FOR_GL_CONTEXT_KHR - comparison missing

6. clGetKernelInfo with params:

• CL_KERNEL_CONTEXT - done,
• CL_KERNEL_PROGRAM - done

7. clGetMemObjectInfo with params:

• CL_MEM_CONTEXT - done,
• CL_MEM_ASSOCIATED_MEMOBJECT

8. clGetMutableCommandInfoKHR with params:

• CL_MUTABLE_COMMAND_COMMAND_QUEUE_KHR - done,
• CL_MUTABLE_COMMAND_COMMAND_BUFFER_KHR - done,
• CL_MUTABLE_DISPATCH_KERNEL_KHR - done

9. clGetProgramInfo with params:

• CL_PROGRAM_CONTEXT - done,
• CL_PROGRAM_DEVICES (including multi-device case) - comparison missing

10. clGetSamplerInfo with param:

• CL_SAMPLER_CONTEXT - done

11. clGetSemaphoreInfoKHR with params:

• CL_SEMAPHORE_CONTEXT_KHR - done,
• CL_SEMAPHORE_DEVICE_HANDLE_LIST_KHR

12. clGetEventInfo with params:

• CL_EVENT_COMMAND_QUEUE - comparison missing,
• CL_EVENT_CONTEXT - done

I will appreciate discussion over these concerns:

1) Is the above list complete, any thoughts on complementing that ? 2) Already covered cases are spreaded among CTS. I guess there is no way around than to follow that scheme with missing cases, right ?