cmd/swarm: fix resource leaks in tests (#19443)

* swarm/api: fix file descriptor leak in NewTestSwarmServer

Swarm storage (localstore) was not closed. That resulted a
"too many open files" error if `TestClientUploadDownloadRawEncrypted`
was run with `-count 1000`.

* cmd/swarm: speed up StartNewNodes() by parallelization

Reduce cluster startup time from 13s to 7s.

* swarm/api: disable flaky TestClientUploadDownloadRawEncrypted with -race

* swarm/storage: disable flaky TestLDBStoreCollectGarbage (-race)

With race detection turned on the disabled cases often fail with:
"ldbstore_test.go:535: expected surplus chunk 150 to be missing, but got no error"

* cmd/swarm: fix process leak in TestACT and TestSwarmUp

Each test run we start 3 nodes, but we did not terminate them. So
those 3 nodes continued eating up 1.2GB (3.4GB with -race) after test
completion.

6b6c4d1c27 changed how we start clusters
to speed up tests. The changeset merged together test cases
and introduced a global cluster. But "forgot" about termination.

Let's get rid of "global cluster" so we have a clear owner of
termination (some time sacrifice), while leaving subtests to use the
same cluster.

swarm/api/http/test_server.go

@@ -33,44 +33,45 @@ type TestServer interface {
 }
 
 func NewTestSwarmServer(t *testing.T, serverFunc func(*api.API) TestServer, resolver api.Resolver) *TestSwarmServer {
-	dir, err := ioutil.TempDir("", "swarm-storage-test")
+	swarmDir, err := ioutil.TempDir("", "swarm-storage-test")
 	if err != nil {
 		t.Fatal(err)
 	}
-	storeparams := storage.NewDefaultLocalStoreParams()
-	storeparams.DbCapacity = 5000000
-	storeparams.CacheCapacity = 5000
-	storeparams.Init(dir)
-	localStore, err := storage.NewLocalStore(storeparams, nil)
+
+	storeParams := storage.NewDefaultLocalStoreParams()
+	storeParams.DbCapacity = 5000000
+	storeParams.CacheCapacity = 5000
+	storeParams.Init(swarmDir)
+	localStore, err := storage.NewLocalStore(storeParams, nil)
 	if err != nil {
-		os.RemoveAll(dir)
+		os.RemoveAll(swarmDir)
 		t.Fatal(err)
 	}
 	fileStore := storage.NewFileStore(localStore, storage.NewFileStoreParams())
-
 	// Swarm feeds test setup
 	feedsDir, err := ioutil.TempDir("", "swarm-feeds-test")
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	rhparams := &feed.HandlerParams{}
-	rh, err := feed.NewTestHandler(feedsDir, rhparams)
+	feeds, err := feed.NewTestHandler(feedsDir, &feed.HandlerParams{})
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	a := api.NewAPI(fileStore, resolver, rh.Handler, nil)
-	srv := httptest.NewServer(serverFunc(a))
+	swarmApi := api.NewAPI(fileStore, resolver, feeds.Handler, nil)
+	apiServer := httptest.NewServer(serverFunc(swarmApi))
+
 	tss := &TestSwarmServer{
-		Server:    srv,
+		Server:    apiServer,
 		FileStore: fileStore,
-		dir:       dir,
+		dir:       swarmDir,
 		Hasher:    storage.MakeHashFunc(storage.DefaultHash)(),
 		cleanup: func() {
-			srv.Close()
-			rh.Close()
-			os.RemoveAll(dir)
+			apiServer.Close()
+			fileStore.Close()
+			feeds.Close()
+			os.RemoveAll(swarmDir)
 			os.RemoveAll(feedsDir)
 		},
 		CurrentTime: 42,