[runtime] Avoid @@isConcatSpreadable lookup for fast path Array.prototype.concat

src/crankshaft/x87/lithium-codegen-x87.cc

Index: src/crankshaft/x87/lithium-codegen-x87.cc
diff --git a/src/crankshaft/x87/lithium-codegen-x87.cc b/src/crankshaft/x87/lithium-codegen-x87.cc
index 67c85d692b25ed21ecfdc34f035981b22b4ac189..4c3c9369084aa8020242f76aa8834f4cb4704eab 100644
--- a/src/crankshaft/x87/lithium-codegen-x87.cc
+++ b/src/crankshaft/x87/lithium-codegen-x87.cc
@@ -3005,9 +3005,9 @@ void LCodeGen::DoLoadKeyedFixedArray(LLoadKeyed* instr) {
     __ j(not_equal, &done);
     if (info()->IsStub()) {
       // A stub can safely convert the hole to undefined only if the array
-      // protector cell contains (Smi) Isolate::kArrayProtectorValid. Otherwise
-      // it needs to bail out.
-      __ mov(result, isolate()->factory()->array_protector());
+      // protector cell contains (Smi) Isolate::kArrayProtectorValid.
+      // Otherwise it needs to bail out.
+      __ LoadRoot(result, Heap::kArrayProtectorRootIndex);
       __ cmp(FieldOperand(result, PropertyCell::kValueOffset),
              Immediate(Smi::FromInt(Isolate::kArrayProtectorValid)));
       DeoptimizeIf(not_equal, instr, Deoptimizer::kHole);