Improve Array.shift() performance for small arrays.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index c9201a80708139b6b4c2922c0a09945cd9bdcf92..7a4de9f4ccad29a23d8605c4738d86492276bb96 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -2258,6 +2258,14 @@ LInstruction* LChunkBuilder::DoTransitionElementsKind(
 }
 
 
+LInstruction* LChunkBuilder::DoArrayShift(HArrayShift* instr) {
+  LOperand* object = UseFixed(instr->object(), r0);
+  LOperand* context = UseFixed(instr->context(), cp);
+  LArrayShift* result = new(zone()) LArrayShift(context, object);
+  return MarkAsCall(DefineFixed(result, r0), instr, CANNOT_DEOPTIMIZE_EAGERLY);
+}
+
+
 LInstruction* LChunkBuilder::DoTrapAllocationMemento(
     HTrapAllocationMemento* instr) {
   LOperand* object = UseRegister(instr->object());