1.0.4.92: faster generic array access

1.0.4.92: faster generic array access

        * Replace the typecase-based HAIRY-DATA-VECTOR-* with a table-driven
          dispatch on widetags
        * Move bounds checking of one-dimension AREFs into HAIRY-DATA-VECTOR-*
          from the caller, so that we can avoid doing a full ARRAY-DIMENSION
          in the common case.
        * 3-5x speedup on generic array accesses