Fix IntBinarySet's comparison operators to be like BinarySetFn

[DarinM223]

Description

In split_gt, IntBinarySet's comparison operators are reversed compared to the BinarySetFn's case expression.

Related Issue

#310

Motivation and Context

For the function:

fun foo () =
  let
    val set1 = IntBinarySet.singleton 5356
    val () = print ("Set1: " ^ showSet set1 ^ "\n")
    val set2 = IntBinarySet.fromList [4986, 5360, 5361]
    val () = print ("Set2: " ^ showSet set2 ^ "\n")
    val result = IntBinarySet.union (set1, set2)
  in
    print ("Set: " ^ showSet result ^ "\n")
  end

results in:

> foo ();
Set1: [5356]
Set2: [4986, 5360, 5361]
Set: [4986, 5356, 4986, 5360, 5361]
val it = (): unit

This results in a set with multiple duplicate numbers added in it. Also intersection doesn't work as expected. Since the SML.NET compiler uses IntBinarySet for its sets of symbols, the result is that after adding symbols to the set through unions, the same symbol appears 4 to 5 times in the set but does not show up when calling intersection with a set with that symbol. This results in it hanging forever when translating valid programs to MIL.

How Has This Been Tested?

This program:

structure Main =
struct
  val showSet = fn t0 =>
    "["
    ^ String.concatWith ", " (List.map Int.toString (IntBinarySet.listItems t0))
    ^ "]"
  fun foo () =
    let
      val set1 = IntBinarySet.singleton 5356
      val () = print ("Set1: " ^ showSet set1 ^ "\n")
      val set2 = IntBinarySet.fromList [4986, 5360, 5361]
      val () = print ("Set2: " ^ showSet set2 ^ "\n")
      val result = IntBinarySet.union (set1, set2)
      val intersect = IntBinarySet.intersection (result, set2)
    in
      print ("Set: " ^ showSet result ^ "\n");
      print ("Intersection: " ^ showSet intersect ^ "\n")
    end
end

results in this afterwards:

- Main.foo ();
Set1: [5356]
Set2: [4986, 5360, 5361]
Set: [4986, 5356, 5360, 5361]
Intersection: [4986, 5360, 5361]
val it = () : unit

SML.NET no longer hangs forever when compiling the raytrace and primes demo programs.

This issue also appears to be in the legacy SML/NJ repository.

[JohnReppy]

The fix looks good