[cleanup] Move ArrayIteratorKind enum to its only use in js-builtin-reducer

Change-Id: I891ff57b7a3a47e3371269b123705cdf6391499b
Reviewed-on: https://chromium-review.googlesource.com/648513Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47830}

src/compiler/js-builtin-reducer.h

@@ -39,6 +39,8 @@ class V8_EXPORT_PRIVATE JSBuiltinReducer final
   Reduction Reduce(Node* node) final;
 
  private:
+  enum class ArrayIteratorKind { kArray, kTypedArray };
+
   Reduction ReduceArrayIterator(Node* node, IterationKind kind);
   Reduction ReduceTypedArrayIterator(Node* node, IterationKind kind);
   Reduction ReduceArrayIterator(Handle<Map> receiver_map, Node* node,

src/globals.h

@@ -1438,10 +1438,6 @@ enum IsolateAddressId {
 }  // namespace internal
 }  // namespace v8
 
-// Used by js-builtin-reducer to identify whether ReduceArrayIterator() is
-// reducing a JSArray method, or a JSTypedArray method.
-enum class ArrayIteratorKind { kArray, kTypedArray };
-
 namespace i = v8::internal;
 
 #endif  // V8_GLOBALS_H_