Fix the runtime implementation of Sys.argv in node

Suppose we have argv.ml like:

    let () = Array.iter print_endline Sys.argv

The standard byte-code interpreter, ocamlrun, doesn't include
its program name at the first of Sys.argv,

    $ ocamlc argv.ml -o argv.out
    $ ./argv.out foo bar
    argv.out
    foo
    bar
    $ ocamlrun argv.out foo bar
    argv.out
    foo
    bar

but the current implementation of Sys.argv in nodejs does as follows:

    $ js_of_ocaml argv.out
    $ node argv.js foo bar
    node
    argv.js
    foo
    bar

It is not a wrong behavior in general, but it is inconvenient to make
the program work both on ocamlrun and nodejs.