Simplify Range#each node

* All Specializations will receive a block since `enumeratorSize` is used.

Author: eregon

src/main/java/org/truffleruby/core/range/RangeNodes.java

@@ -25,7 +25,6 @@
 import org.truffleruby.core.cast.ToIntNode;
 import org.truffleruby.core.klass.RubyClass;
 import org.truffleruby.core.proc.RubyProc;
-import org.truffleruby.language.Nil;
 import org.truffleruby.language.RubyContextNode;
 import org.truffleruby.language.RubyGuards;
 import org.truffleruby.language.RubyNode;
@@ -137,24 +136,15 @@ protected RubyLongRange eachLong(RubyLongRange range, RubyProc block) {
             return range;
         }
 
-        private Object eachInternal(VirtualFrame frame, RubyRange range, Object block) {
+        @Specialization
+        protected Object eachObject(RubyObjectRange range, RubyProc block) {
             if (eachInternalCall == null) {
                 CompilerDirectives.transferToInterpreterAndInvalidate();
                 eachInternalCall = insert(DispatchNode.create());
             }
 
             return eachInternalCall.callWithBlock(range, "each_internal", block);
         }
-
-        @Specialization
-        protected Object eachObject(VirtualFrame frame, RubyLongRange range, Nil block) {
-            return eachInternal(frame, range, block);
-        }
-
-        @Specialization
-        protected Object each(VirtualFrame frame, RubyObjectRange range, Object block) {
-            return eachInternal(frame, range, block);
-        }
     }
 
     @CoreMethod(names = "exclude_end?")