Fix and re-enable Effects failing feature tests

[miguep]

https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-test/pullrequest/1739?_a=overview disables failing tests.

This test case was disabled as it fails in .NET Core, it passes in .NET Framework:
/Name="NegativeTest" /SubArea="Arrowhead\NegativeTest"