Tests from anonymous namespaces cannot be executed

[twollgam]

Test Adapter for Google Test: 0.17.0.23 Visual Studio: 17.6.1

If one select tests from an anonymous namespace they cannot be executed. The reason is that the command line option --gtest_filter does not contain a matching pattern, for example:

-gtest_filter=`anonymous namespace'.AUnitTest.test_something

1. I think that the goolge test framework does not support this kind of namespace matching
2. The command line is invalid cause the used quotes does not encapsulate the included space. So the parameter is broken in two pieces/arguments.