Stop swallowing JTF exceptions

src/EditorFeatures/TestUtilities/Workspaces/TestWorkspace.cs

@@ -194,7 +194,6 @@ private static IList<Exception> Flatten(ICollection<Exception> exceptions)
             var aggregate = new AggregateException(exceptions);
             return aggregate.Flatten().InnerExceptions
                 .Select(UnwrapException)
-                .Where(ex => !(ex is JoinableTaskContextException))
                 .ToList();
         }