[Interpreter] Optimize equality check with null/undefined with a check on the map.

src/interpreter/bytecode-generator.h

Index: src/interpreter/bytecode-generator.h
diff --git a/src/interpreter/bytecode-generator.h b/src/interpreter/bytecode-generator.h
index 7b49021b38d8765e3d83b6e0b2b05598518e0bab..96405f6be158000d4185ec0fca20def90bf5ed69 100644
--- a/src/interpreter/bytecode-generator.h
+++ b/src/interpreter/bytecode-generator.h
@@ -195,6 +195,7 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
   Handle<Name> home_object_symbol() const { return home_object_symbol_; }
   Handle<Name> prototype_string() const { return prototype_string_; }
   Handle<FixedArray> empty_fixed_array() const { return empty_fixed_array_; }
+  const AstRawString* undefined_string() const { return undefined_string_; }
 
   Zone* zone_;
   BytecodeArrayBuilder* builder_;
@@ -218,6 +219,7 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
   Handle<Name> home_object_symbol_;
   Handle<Name> prototype_string_;
   Handle<FixedArray> empty_fixed_array_;
+  const AstRawString* undefined_string_;
 };
 
 }  // namespace interpreter