[arm][arm64] fix code for InstanceofStub

R=ulan@chromium.org, bmeurer@chromium.org

BUG=

Review URL: https://codereview.chromium.org/657813002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24654 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/code-stubs-arm.cc

@@ -1441,7 +1441,7 @@ void InstanceofStub::Generate(MacroAssembler* masm) {
   __ b(ne, &slow);
 
   // Null is not instance of anything.
-  __ cmp(scratch, Operand(isolate()->factory()->null_value()));
+  __ cmp(object, Operand(isolate()->factory()->null_value()));
   __ b(ne, &object_not_null);
   if (ReturnTrueFalseObject()) {
     __ Move(r0, factory->false_value());

src/arm64/code-stubs-arm64.cc

@@ -1569,7 +1569,7 @@ void InstanceofStub::Generate(MacroAssembler* masm) {
   __ Mov(result, res_false);
 
   // Null is not instance of anything.
-  __ Cmp(object_type, Operand(isolate()->factory()->null_value()));
+  __ Cmp(object, Operand(isolate()->factory()->null_value()));
   __ B(ne, &object_not_null);
   __ Ret();