Support array literals with FAST_DOUBLE_ELEMENTS ElementsKind.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index ba22ae9907f6cfba15fae53b78b6f54fb6ca4fde..a0e5346b989f53a6bf9ad228f2b7ac2cb0e696ef 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1225,7 +1225,10 @@ void HConstant::PrintDataTo(StringStream* stream) {
 
 
 bool HArrayLiteral::IsCopyOnWrite() const {
-  return constant_elements()->map() == HEAP->fixed_cow_array_map();
+  Handle<FixedArray> constant_elements = this->constant_elements();
+  FixedArrayBase* constant_elements_values =
+      FixedArrayBase::cast(constant_elements->get(1));
+  return constant_elements_values->map() == HEAP->fixed_cow_array_map();
 }