[es6] Reintroduce the instanceof operator in the backends.

src/crankshaft/arm64/lithium-codegen-arm64.cc

Index: src/crankshaft/arm64/lithium-codegen-arm64.cc
diff --git a/src/crankshaft/arm64/lithium-codegen-arm64.cc b/src/crankshaft/arm64/lithium-codegen-arm64.cc
index 41e62d73de09aaa875b0f09118dec2f71756aa87..049a7bfe9ccd3f91eb87ccf87b38034e4d927a68 100644
--- a/src/crankshaft/arm64/lithium-codegen-arm64.cc
+++ b/src/crankshaft/arm64/lithium-codegen-arm64.cc
@@ -2802,16 +2802,6 @@ void LCodeGen::DoInnerAllocatedObject(LInnerAllocatedObject* instr) {
 }
 
 
-void LCodeGen::DoInstanceOf(LInstanceOf* instr) {
-  DCHECK(ToRegister(instr->context()).is(cp));
-  DCHECK(ToRegister(instr->left()).is(InstanceOfDescriptor::LeftRegister()));
-  DCHECK(ToRegister(instr->right()).is(InstanceOfDescriptor::RightRegister()));
-  DCHECK(ToRegister(instr->result()).is(x0));
-  InstanceOfStub stub(isolate());
-  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
-}
-
-
 void LCodeGen::DoHasInPrototypeChainAndBranch(
     LHasInPrototypeChainAndBranch* instr) {
   Register const object = ToRegister(instr->object());