[cleanup] Remove unused InternalPackedArray.

Inside of V8 there's no use of InternalPackedArray left, so no need to
keep that around.

R=yangguo@chromium.org

Change-Id: I819fc400ef46353339596dec98b70df2d442ed47
Reviewed-on: https://chromium-review.googlesource.com/583653Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46853}

src/bootstrapper.cc

@@ -4372,7 +4372,6 @@ bool Genesis::InstallNatives(GlobalContextType context_type) {
     Handle<JSFunction> array_function =
         InstallInternalArray(utils, "InternalArray", HOLEY_ELEMENTS);
     native_context()->set_internal_array_function(*array_function);
-    InstallInternalArray(utils, "InternalPackedArray", PACKED_ELEMENTS);
   }
 
   // Run the rest of the native scripts.

src/js/array.js

@@ -15,7 +15,6 @@ var GetIterator;
 var GetMethod;
 var GlobalArray = global.Array;
 var InternalArray = utils.InternalArray;
-var InternalPackedArray = utils.InternalPackedArray;
 var MaxSimple;
 var MinSimple;
 var ObjectHasOwnProperty = global.Object.prototype.hasOwnProperty;
@@ -1355,13 +1354,6 @@ utils.SetUpLockedPrototype(InternalArray, GlobalArray(), [
   "splice", ArraySplice
 ]);
 
-utils.SetUpLockedPrototype(InternalPackedArray, GlobalArray(), [
-  "join", ArrayJoin,
-  "pop", ArrayPop,
-  "push", ArrayPush,
-  "shift", ArrayShift
-]);
-
 // V8 extras get a separate copy of InternalPackedArray. We give them the basic
 // manipulation methods.
 utils.SetUpLockedPrototype(extrasUtils.InternalPackedArray, GlobalArray(), [