Debug: Add typemap.c

[hzhou]

Pull Request Description

Provide two internal utility functions:

1. struct typemap *MPIR_type_get_typemap(MPI_Datatype dt)
2. struct typesig *MPIR_type_get_typesig(MPI_Datatype dt)

with

struct typemap {
    MPI_Aint n;
    MPI_Datatype *types;
    MPI_Aint *disps;
};

struct typesig {
    MPI_Aint n;
    MPI_Datatype *types;
    MPI_Aint *counts;
};

These two function returns an internal data structure with allocated memory, so it is difficult to expose to the user. So we also provide two user functions that just prints to stdout (I know, not ideal):

1. MPIX_Type_dump_typemap(MPI_Datatype datatype)
2. MPIX_Type_dump_typesig(MPI_Datatype datatype)

Author Checklist

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