[es6] Reintroduce the instanceof operator in the backends.

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index 9fbade7733a6a33af5dfde09bac750d1662a1dfd..3cbe8178c38465366b61725c50ac4c6e32487786 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -1262,29 +1262,6 @@ void Builtins::Generate_DatePrototype_GetField(MacroAssembler* masm,
 }
 
 // static
-void Builtins::Generate_FunctionHasInstance(MacroAssembler* masm) {
-  // ----------- S t a t e -------------
-  //  -- rax     : argc
-  //  -- rsp[0]  : return address
-  //  -- rsp[8]  : first argument (left-hand side)
-  //  -- rsp[16] : receiver (right-hand side)
-  // -----------------------------------
-
-  {
-    FrameScope scope(masm, StackFrame::INTERNAL);
-    __ movp(InstanceOfDescriptor::LeftRegister(),
-            Operand(rbp, 2 * kPointerSize));  // Load left-hand side.
-    __ movp(InstanceOfDescriptor::RightRegister(),
-            Operand(rbp, 3 * kPointerSize));  // Load right-hand side.
-    InstanceOfStub stub(masm->isolate(), true);
-    __ CallStub(&stub);
-  }
-
-  // Pop the argument and the receiver.
-  __ ret(2 * kPointerSize);
-}
-
-// static
 void Builtins::Generate_FunctionPrototypeApply(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax     : argc