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

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

Index: src/crankshaft/arm/lithium-codegen-arm.cc
diff --git a/src/crankshaft/arm/lithium-codegen-arm.cc b/src/crankshaft/arm/lithium-codegen-arm.cc
index 62929a2dbb9f53a08871a6ad07001d5def5cabc2..802647fc2f74ad713d8ea06979ce58fb5f22af83 100644
--- a/src/crankshaft/arm/lithium-codegen-arm.cc
+++ b/src/crankshaft/arm/lithium-codegen-arm.cc
@@ -2975,8 +2975,8 @@ void LCodeGen::DoLoadKeyedFixedArray(LLoadKeyed* instr) {
     __ b(ne, &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.
+      // protector cell contains (Smi) Isolate::kArrayProtectorValid.
+      // Otherwise it needs to bail out.

[Toon Verwaest, 2016/03/31 08:09:46]

Spurious change ... :)

       __ LoadRoot(result, Heap::kArrayProtectorRootIndex);
       __ ldr(result, FieldMemOperand(result, Cell::kValueOffset));
       __ cmp(result, Operand(Smi::FromInt(Isolate::kArrayProtectorValid)));