Merge pull request #63444 from deads2k/client-07-gc-dynamic

Automatic merge from submit-queue (batch tested with PRs 63526, 60371, 63444). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

update garbage collection to use the new dynamic client

Update GC to use the new and easy to use dynamic client.  This is one of two remaining stragglers.

@kubernetes/sig-api-machinery-pr-reviews 
@caesarxuchao @ironcladlou 

```release-note
NONE
```

test/integration/garbagecollector/garbage_collector_test.go

@@ -224,9 +224,6 @@ func setupWithServer(t *testing.T, result *kubeapiservertesting.TestServer, work
 	restMapper.Reset()
 	deletableResources := garbagecollector.GetDeletableResources(discoveryClient)
 	config := *result.ClientConfig
-	config.ContentConfig = dynamic.ContentConfig()
-	metaOnlyClientPool := dynamic.NewClientPool(&config, restMapper, dynamic.LegacyAPIPathResolverFunc)
-	clientPool := dynamic.NewClientPool(&config, restMapper, dynamic.LegacyAPIPathResolverFunc)
 	dynamicClient, err := dynamic.NewForConfig(&config)
 	if err != nil {
 		t.Fatalf("failed to create dynamicClient: %v", err)
@@ -235,8 +232,7 @@ func setupWithServer(t *testing.T, result *kubeapiservertesting.TestServer, work
 	alwaysStarted := make(chan struct{})
 	close(alwaysStarted)
 	gc, err := garbagecollector.NewGarbageCollector(
-		metaOnlyClientPool,
-		clientPool,
+		dynamicClient,
 		restMapper,
 		deletableResources,
 		garbagecollector.DefaultIgnoredResources(),