mpix: add MPIX_Query_pointer_attr

[hzhou]

Pull Request Description

It is not always easy to check what kind of memory type user has as seen by MPI. For example, a memory from a Python library. Add MPIX_Query_pointer_attr for the debugging purpose.

Synopsis:

int rc, type, device;
rc = MPIX_Query_pointer_attr(sum, &type, &device);
printf("MPIX_Query_pointer_attr: sum=%p, rc=%x, type=%d, device=%d\n", sum, rc, type, device);

, where type is one of -

/* MPIX_Query_pointer_attr */
enum MPIX_Pointer_type {
    MPIX_POINTER_UNREGISTERED_HOST = 0,
    MPIX_POINTER_REGISTERED_HOST,
    MPIX_POINTER_DEV,
    MPIX_POINTER_MANAGED
};

[skip warnings]

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