Fix test failures due to semantic_analysis_only flag.

Author: Guido van Rossum

mypy/build.py

@@ -1420,6 +1420,8 @@ def type_check_first_pass(self) -> None:
 
     def type_check_second_pass(self) -> None:
         manager = self.manager
+        if self.options.semantic_analysis_only:
+            return
         with self.wrap_context():
             self.type_checker.check_second_pass()
             manager.all_types.update(self.type_checker.type_map)