Try to fix and enable a ThreadPool.CompletedWorkItemCount test and add more info about failures

src/libraries/System.Threading.Overlapped/tests/ThreadPoolBoundHandle_IntegrationTests.netcoreapp.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Threading;
 using System.Threading.Tests;
 using Xunit;
@@ -9,11 +10,23 @@ public partial class ThreadPoolBoundHandleTests
 {
     [Fact]
     [PlatformSpecific(TestPlatforms.Windows)] // ThreadPoolBoundHandle.BindHandle is not supported on Unix
-    [ActiveIssue("https://github.com/dotnet/runtime/issues/49700")]
     public unsafe void MultipleOperationsOverSingleHandle_CompletedWorkItemCountTest()
     {
         long initialCompletedWorkItemCount = ThreadPool.CompletedWorkItemCount;
-        MultipleOperationsOverMultipleHandles();
-        ThreadTestHelpers.WaitForCondition(() => ThreadPool.CompletedWorkItemCount - initialCompletedWorkItemCount >= 2);
+        MultipleOperationsOverSingleHandle();
+        long changeInCompletedWorkItemCount = 0;
+        try
+        {
+            ThreadTestHelpers.WaitForCondition(() =>
+            {
+                changeInCompletedWorkItemCount = ThreadPool.CompletedWorkItemCount - initialCompletedWorkItemCount;
+                return changeInCompletedWorkItemCount >= 2;
+            });
+        }
+        catch (Exception ex)
+        {
+            // Test likely timed out, include the change for more information
+            throw new AggregateException($"changeInCompletedWorkItemCount: {changeInCompletedWorkItemCount}", ex);
+        }
     }
 }