KT-944 iterations over empty ranges

stdlib/src/jet/ByteRange.java

@@ -30,6 +30,10 @@ public final class ByteRange implements Range<Byte>, ByteIterable, JetObject {
         return start;
     }
 
+    public byte getIteratorStart () {
+        return count == 0 ? 1 : start;
+    }
+
     public byte getEnd() {
         return (byte) (count < 0 ? start + count + 1: count == 0 ? 0 : start+count-1);
     }

stdlib/src/jet/CharRange.java

@@ -30,6 +30,10 @@ public final class CharRange implements Range<Character>, CharIterable, JetObjec
         return start;
     }
 
+    public char getIteratorStart () {
+        return count == 0 ? 1 : start;
+    }
+
     public char getEnd() {
         return (char) (count < 0 ? start + count + 1: count == 0 ? 0 : start+count-1);
     }

stdlib/src/jet/IntRange.java

@@ -33,6 +33,10 @@ public final class IntRange implements Range<Integer>, IntIterable, JetObject {
         return count < 0;
     }
 
+    public int getIteratorStart () {
+        return count == 0 ? 1 : start;
+    }
+    
     public int getStart() {
         return start;
     }

stdlib/src/jet/LongRange.java

@@ -37,6 +37,10 @@ public final class LongRange implements Range<Long>, LongIterable, JetObject {
         return start;
     }
 
+    public long getIteratorStart () {
+        return count == 0 ? 1 : start;
+    }
+
     public long getEnd() {
         return count < 0 ? start + count + 1: count == 0 ? 0 : start+count-1;
     }

stdlib/src/jet/ShortRange.java

@@ -37,6 +37,10 @@ public final class ShortRange implements Range<Short>, ShortIterable, JetObject
         return start;
     }
 
+    public int getIteratorStart () {
+        return count == 0 ? 1 : start;
+    }
+
     public short getEnd() {
         return (short) (count < 0 ? start + count + 1: count == 0 ? 0 : start+count-1);
     }