test_win32ole_event.rb: retry random failure

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66378 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/win32ole/test_win32ole_event.rb

@@ -138,7 +138,8 @@ if defined?(WIN32OLE_EVENT)
           handler1
         }
         message_loop
-        assert_equal("handler1", @event1)
+        # @event1 randomly becomes "" here: https://ci.appveyor.com/project/ruby/ruby/builds/20975541/job/b380m0q9ed0rdv7v
+        assert_match_with_retries(/\Ahandler1\z/, :@event1)
       end
 
       private