Respect TraitFilters

Change 1
Put a helper in here and use reflection to get the ITestCaseFilterExpression.  In V11 it was ITestCaseFilterExpression TestCaseFilter { get; },  in V12+ ITestCaseFilterExpression GetTestCaseFilter(IEnumerable<string> supportedProperties, Func<string, TestProperty> propertyProvider);  Should be fine to start with try and find v12+ and handle null ITestCaseFilterExpression.