Modify the local_accessor printer to display data as a linear index from a
decorated pointer. This is necessary to retain the address space qualifier.

A simple array printer was added to print local memory like a vector.  The
array printer limits the elements displayed based on GDB's print options to
avoid displaying large data sets. This can be adjusted in GDB:

    (gdb) p -elements 4 -- local_accessor_1d
    $1 = sycl::local_accessor range 10 = {0, 1, 2, 3...}

    (gdb) show print elements
    Limit on string chars or array elements to print is 200.