Fix dynamic param tests.

jedi/evaluate/context.py

@@ -43,6 +43,9 @@ class Context(object):
     def eval_stmt(self, stmt, seek_name=None):
         return self.evaluator.eval_statement(self, stmt, seek_name)
 
+    def eval_trailer(self, types, trailer):
+        return self.evaluator.eval_trailer(self, types, trailer)
+
 
 class TreeContext(Context):
     pass