pull up common getByteSlow definition

Author: Nicolas Laurent

src/main/java/org/truffleruby/core/rope/ConcatRope.java

@@ -77,11 +77,6 @@ Rope withBinaryEncoding() {
                 balanced);
     }
 
-    @Override
-    public byte getByteSlow(int index) {
-        return RopeOperations.getByteSlow(this, index);
-    }
-
     public ManagedRope getLeft() {
         return left;
     }

src/main/java/org/truffleruby/core/rope/ManagedRope.java

@@ -39,6 +39,11 @@ public final int characterLength() {
         return characterLength;
     }
 
+    @Override
+    protected byte getByteSlow(int index) {
+        return RopeOperations.getByteSlow(this, index);
+    }
+
     @Override
     public final byte[] getBytes() {
         if (bytes == null) {

src/main/java/org/truffleruby/core/rope/RepeatingRope.java

@@ -68,11 +68,6 @@ protected byte[] getBytesSlow() {
         return super.getBytesSlow();
     }
 
-    @Override
-    protected byte getByteSlow(int index) {
-        return RopeOperations.getByteSlow(this, index);
-    }
-
     public ManagedRope getChild() {
         return child;
     }

src/main/java/org/truffleruby/core/rope/SubstringRope.java

@@ -80,11 +80,6 @@ protected byte[] getBytesSlow() {
         return super.getBytesSlow();
     }
 
-    @Override
-    public byte getByteSlow(int index) {
-        return RopeOperations.getByteSlow(this, index);
-    }
-
     public ManagedRope getChild() {
         return child;
     }