Fix stdlib mlis

[ncik-roberts]

Resolve conflicts in stdlib mlis. These are almost always resolutions that prefer tip-5, but a handful of cases incorporate comments/documentation from tip-jst.

I make one update to gc.ml because, while we're still using the ocaml 4 runtime, we don't have to replace these functions with no-ops. When we finish merging the ocaml 5 runtime, we'll be flagged that these external functions don't exist and can figure out that they should be replaced with no-ops then.

Testing:

for x in stdlib/*.mli; do
  file=$(basename ${x%.mli});
  if echo $file | grep 'camlinternal\|stdlib\|std_exit'; then
    cmi=$file
  else
    cmi=stdlib__${file^}
  fi

  dune b --workspace=duneconf/runtime_stdlib.ws _build/runtime_stdlib/stdlib/.stdlib.objs/byte/$cmi.cmi
done

You'll see some syntax errors for JS-internal features: local_, float#, global_, but things otherwise build

[goldfirere]

Reviewing