::testing::Test::RecordProperty adding child elements instead of testcase attributes in the output XML

As an example, I've modified one of the tests in `sample1_unittest` the following way:
```c++
TEST(FactorialTest, Negative) {
EXPECT_EQ(1, Factorial(-5));
EXPECT_EQ(1, Factorial(-1));
EXPECT_GT(Factorial(-10), 0);
::testing::Test::RecordProperty("Hello", "World");
}
```
Running the test with `sample1_unittest.exe --gtest_output=xml` results in the following XML output:
```xml

```

I was expecting based on [Logging Additional Information](https://github.com/google/googletest/blob/master/googletest/docs/advanced.md#logging-additional-information) the Negative testcase to have a `Hello` atttribute with `World` value like this:
```xml

```

Is this a bug or the way it's supposed to work?