Compiler: fix a bug Js_output with debuginfo enabled.
Compiler: fix a bug Js_output with debuginfo enabled.

EXPR DIV COMMENT EXPR can generate EOL_COMMENT
Correct: a/ /*comment*/b
Wrong:   a//*comment*/b

OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,alainfrisch/js_of_ocaml