[typedarray] Properly initialize JSTypedArray::length with Smi.

src/runtime/runtime-typedarray.cc

Index: src/runtime/runtime-typedarray.cc
diff --git a/src/runtime/runtime-typedarray.cc b/src/runtime/runtime-typedarray.cc
index 963f1862bc7b965d77bb7a3733541500d7f7bf01..ba422bf01ec3fa2c8fc852290ef78275381a6d36 100644
--- a/src/runtime/runtime-typedarray.cc
+++ b/src/runtime/runtime-typedarray.cc
@@ -200,11 +200,9 @@ RUNTIME_FUNCTION(Runtime_TypedArrayInitializeFromArrayLike) {
   size_t length = 0;
   if (source->IsJSTypedArray() &&
       JSTypedArray::cast(*source)->type() == array_type) {
-    length_obj = handle(JSTypedArray::cast(*source)->length(), isolate);
     length = JSTypedArray::cast(*source)->length_value();
   } else {
     CHECK(TryNumberToSize(*length_obj, &length));
-    CHECK(length_obj->IsSmi());
   }
 
   if ((length > static_cast<unsigned>(Smi::kMaxValue)) ||
@@ -247,6 +245,7 @@ RUNTIME_FUNCTION(Runtime_TypedArrayInitializeFromArrayLike) {
   Handle<Object> byte_length_obj(
       isolate->factory()->NewNumberFromSize(byte_length));
   holder->set_byte_length(*byte_length_obj);
+  length_obj = isolate->factory()->NewNumberFromSize(length);
   holder->set_length(*length_obj);
 
   Handle<FixedTypedArrayBase> elements =