[ASTGen] **** Enable ParserASTGen for Testing ****

Author: rintaro

lib/Basic/LangOptions.cpp

@@ -56,6 +56,9 @@ LangOptions::LangOptions() {
   enableFeature(Feature::BorrowingSwitch);
   enableFeature(Feature::MoveOnlyPartialConsumption);
 
+  // ASTGen.
+  enableFeature(Feature::ParserASTGen);
+
   // Enable any playground options that are enabled by default.
 #define PLAYGROUND_OPTION(OptionName, Description, DefaultOn, HighPerfOn) \
   if (DefaultOn) \