[turbofan] Use CompareNilIC for abstract equality with null/undefined.

src/code-factory.cc

Index: src/code-factory.cc
diff --git a/src/code-factory.cc b/src/code-factory.cc
index 845c61e69165884053a581c2ff557ffae8d3c196..37179f38c938c27b9e4e21b165575c94fbeccae9 100644
--- a/src/code-factory.cc
+++ b/src/code-factory.cc
@@ -130,6 +130,13 @@ Callable CodeFactory::CompareIC(Isolate* isolate, Token::Value op,
 
 
 // static
+Callable CodeFactory::CompareNilIC(Isolate* isolate, NilValue nil_value) {
+  Handle<Code> code = CompareNilICStub::GetUninitialized(isolate, nil_value);
+  return Callable(code, CompareNilDescriptor(isolate));
+}
+
+
+// static
 Callable CodeFactory::BinaryOpIC(Isolate* isolate, Token::Value op,
                                  Strength strength) {
   BinaryOpICStub stub(isolate, op, strength);