comment out fast forest trainer, per discussion on ML.NET open issue dotnet#1983, for now, to run E2E w/o exceptions (dotnet#7)

Author: daholste

src/AutoML/TrainerExtensions/TrainerExtensionCatalog.cs

@@ -58,7 +58,7 @@ private static IEnumerable<ITrainerExtension> GetBinaryLearners(int maxIteration
 
             learners.AddRange(new ITrainerExtension[] {
                 new LogisticRegressionBinaryExtension(),
-                new FastForestBinaryExtension(),
+                //new FastForestBinaryExtension(),
                 new SgdBinaryExtension()
             });