Fix broken test

Author: saul

Ix.NET/Source/System.Linq.Async.Tests/System/Linq/AsyncEnumerableTests.cs

@@ -23,7 +23,7 @@ protected Task<TException> AssertThrowsAsync<TException>(Task t)
 
         protected async Task AssertThrowsAsync(Task t, Exception e)
         {
-            var ex = await AssertThrowsAsync<Exception>(t);
+            var ex = await Assert.ThrowsAnyAsync<Exception>(() => t);
             Assert.Same(e, ex);
         }