Revert optimization in Enumerable.Range

The new implementation does not handle the edge case where
Enumerable.Range enumerates up to Int32.MaxValue. If values are given such
that the end value will be Int32.MaxValue, no values are enumerated. This
change simply reverts that change.

Author: mellinoe

src/System.Linq/src/System/Linq/Enumerable.cs

@@ -1472,8 +1472,7 @@ public static IEnumerable<int> Range(int start, int count)
 
         private static IEnumerable<int> RangeIterator(int start, int count)
         {
-            for (int end = start + count; start < end; start++)
-                yield return start;
+            for (int i = 0; i < count; i++) yield return start + i;
         }
 
         public static IEnumerable<TResult> Repeat<TResult>(TResult element, int count)