Auto-generate test exclusion lists #3389
Description
The mono archive contains unit test exclusion lists, e.g.:
$ unzip -l android-debug-Darwin-e6f5369c2d24aa2de511a52c8a58956c3283c4e4.zip | grep txt$
76 06-27-2019 18:05 android-bcl/monodroid/tests/nunit-excludes.txt
94 06-27-2019 18:05 android-bcl/monodroid/tests/xunit-excludes.txt
We should generate the files tests/BCL-Tests/Xamarin.Android.Bcl-Tests/nunit-excluded-tests.txt and tests/BCL-Tests/Xamarin.Android.Bcl-Tests/xunit-excluded-tests.txt based on these files.