message: Implemented testID prop on bar button
diff: @@ -55,6 +55,9 @@ using namespace facebook::react;
  [self.button setTitleTextAttributes:attributes forState:UIControlStateNormal];
  [self.button setTitleTextAttributes:attributes forState:UIControlStateSelected];
  }
  + NSString *testID = [[NSString alloc] initWithUTF8String: newViewProps.testID.c_str()];
  + if (self.button.accessibilityIdentifier != testID)
  + self.button.accessibilityIdentifier = testID;
  [super updateProps:props oldProps:oldProps];
  }
  