fix InstanceDataCollectionCollection_CopyTo by retrying on 0 values

Previously, when pcc.ReadCategory() returned 0 values, we did not retry,
which broke the test that asserted its length > 0. This time, we retry
when there are 0 values, by triggering the RetryHelper's exception
handler.

Fixes dotnet#68291

src/libraries/System.Diagnostics.PerformanceCounter/tests/InstanceDataTests.cs

@@ -124,8 +124,16 @@ public static void InstanceDataCollectionCollection_CopyTo()
 
         public static InstanceDataCollectionCollection GetInstanceDataCollectionCollection()
         {
-            PerformanceCounterCategory pcc =  Helpers.RetryOnAllPlatforms(() => new PerformanceCounterCategory("Processor"));
-            return Helpers.RetryOnAllPlatforms(() => pcc.ReadCategory());
+            PerformanceCounterCategory pcc = Helpers.RetryOnAllPlatforms(() => new PerformanceCounterCategory("Processor"));
+            return Helpers.RetryOnAllPlatforms(() =>
+            {
+                var idcc = pcc.ReadCategory();
+                if (idcc.Values.Count == 0)
+                {
+                    throw new Exception();
+                }
+                return idcc;
+            });
         }
 
         public static InstanceDataCollection GetInstanceDataCollection()