Move toString() from primitive ranges to Range

The same can't be done with progressions, because its toString() checks if an
increment is greater than zero, but Progression.increment is of type Number,
which is not Comparable<Int>

generators/src/org/jetbrains/jet/generators/runtime/ranges.kt

@@ -71,8 +71,6 @@ class GenerateRanges(val out: PrintWriter) {
 
     fun hashCode()$hashCode
 
-    fun toString() = "${"\$start..\$end"}"
-
     class object {
         public val EMPTY: $range = $range($emptyBounds)
     }