ocamldebug: fix printing of variables of lazy type
ocamldebug: fix printing of variables of lazy type

"print a" in ocamldebug when a is a forced lazy value segfaults on all
OCaml versions I tested it on. This comes from the fact that the
debugcomm.ml re-implementation of the Obj module (talking over the
debugging socket) implements Obj.tag without special-casing integers
(that is, testing is_block first), and always assumes its input is
a block.

git-svn-id: e7e61699ce1738538ffebb75374fbea0924bc775@15658 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

msprotz/ocaml,yunxing/ocaml,msprotz/ocaml,gerdstolpmann/ocaml,yunxing/ocaml,yunxing/ocaml,msprotz/ocaml,yunxing/ocaml,eliberis/ocaml,gerdstolpmann/ocaml,eliberis/ocaml,eliberis/ocaml,msprotz/ocaml,msprotz/ocaml,eliberis/ocaml,gerdstolpmann/ocaml,yunxing/ocaml,eliberis/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml