[es6] Reintroduce the instanceof operator in the backends.

src/crankshaft/mips64/lithium-codegen-mips64.cc

Index: src/crankshaft/mips64/lithium-codegen-mips64.cc
diff --git a/src/crankshaft/mips64/lithium-codegen-mips64.cc b/src/crankshaft/mips64/lithium-codegen-mips64.cc
index eb091b4620efdccae2b2551a1dfbf5e99272250f..d2c8b6a258d7bb8e07f37abc3661aedc142133fd 100644
--- a/src/crankshaft/mips64/lithium-codegen-mips64.cc
+++ b/src/crankshaft/mips64/lithium-codegen-mips64.cc
@@ -2501,18 +2501,6 @@ void LCodeGen::DoCmpMapAndBranch(LCmpMapAndBranch* instr) {
 }
 
 
-void LCodeGen::DoInstanceOf(LInstanceOf* instr) {
-  DCHECK(ToRegister(instr->context()).is(cp));
-  Label true_label, done;
-  DCHECK(ToRegister(instr->left()).is(InstanceOfDescriptor::LeftRegister()));
-  DCHECK(ToRegister(instr->right()).is(InstanceOfDescriptor::RightRegister()));
-  DCHECK(ToRegister(instr->result()).is(v0));
-
-  InstanceOfStub stub(isolate());
-  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
-}
-
-
 void LCodeGen::DoHasInPrototypeChainAndBranch(
     LHasInPrototypeChainAndBranch* instr) {
   Register const object = ToRegister(instr->object());