Fix LiveInterval.Split (#1660)

Before when splitting intervals, the end of the range would be included
in the split check, this can produce empty ranges in the child split.

This in turn can affect spilling decisions since the child split will
have a different start position and this empty range will get a register
and move to the active set for a brief moment.

For example:

  A = [153, 172[; [1899, 1916[; [1991, 2010[; [2397, 2414[; ...

  Split(A, 1916)

  A0 = [153, 172[; [1899, 1916[
  A1 = [1916, 1916[; [1991, 2010[; [2397, 2414[; ...

ARMeilleure/CodeGen/RegisterAllocators/LiveInterval.cs

@@ -287,7 +287,7 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
             {
                 LiveRange range = _ranges[splitIndex];
 
-                if (position > range.Start && position <= range.End)
+                if (position > range.Start && position < range.End)
                 {
                     right._ranges.Add(new LiveRange(position, range.End));