Inline Array.shift() fast path instead of using a code stub.

src/mips/lithium-mips.cc

Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index 333d8499c4fa2e6474f23d82116671b183c587d7..c7939157f9cc1a95d94dde2d652f56bf331dcb8d 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -2235,14 +2235,6 @@ LInstruction* LChunkBuilder::DoTransitionElementsKind(
 }
 
 
-LInstruction* LChunkBuilder::DoArrayShift(HArrayShift* instr) {
-  LOperand* object = UseFixed(instr->object(), a0);
-  LOperand* context = UseFixed(instr->context(), cp);
-  LArrayShift* result = new(zone()) LArrayShift(context, object);
-  return MarkAsCall(DefineFixed(result, v0), instr, CANNOT_DEOPTIMIZE_EAGERLY);
-}
-
-
 LInstruction* LChunkBuilder::DoTrapAllocationMemento(
     HTrapAllocationMemento* instr) {
   LOperand* object = UseRegister(instr->object());