make a test compatible with runtime async.

Author: VSadov

src/libraries/System.Runtime/tests/System.Threading.Tasks.Tests/System.Runtime.CompilerServices/AsyncTaskMethodBuilderTests.cs

@@ -670,8 +670,12 @@ public void AsyncTaskMethodBuilder_Completed_RemovedFromTracking()
                     t.Wait();
                 }
 
-                int activeCount = ((dynamic)typeof(Task).GetField("s_currentActiveTasks", BindingFlags.NonPublic | BindingFlags.Static).GetValue(null)).Count;
-                Assert.InRange(activeCount, 0, 10); // some other tasks may be created by the runtime, so this is just using a reasonably small upper bound
+                object activeTasks = typeof(Task).GetField("s_currentActiveTasks", BindingFlags.NonPublic | BindingFlags.Static).GetValue(null);
+                if (activeTasks is not null)
+                {
+                    int activeCount = ((dynamic)activeTasks).Count;
+                    Assert.InRange(activeCount, 0, 10); // some other tasks may be created by the runtime, so this is just using a reasonably small upper bound
+                }
             }).Dispose();
         }
 

testOut5.txt

@@ -0,0 +1,9 @@
+  Determining projects to restore...
+  Tool 'coverlet.console' (version '6.0.4') was restored. Available commands: coverlet
+  Tool 'dotnet-reportgenerator-globaltool' (version '5.4.3') was restored. Available commands: reportgenerator
+  Tool 'microsoft.dotnet.xharness.cli' (version '10.0.0-prerelease.25475.1') was restored. Available commands: xharness
+  Tool 'microsoft.visualstudio.slngen.tool' (version '12.0.15') was restored. Available commands: slngen
+  
+  Restore was successful.
+  All projects are up-to-date for restore.
+  Determining projects to restore...