playground: change rt.New to veyron2.Init.

This is dependent on https://vanadium-review.googlesource.com/#/c/1637/

Change-Id: Idd3baa69cfa0ee3f4a60b6cdfe382a59d5d01e21
diff --git a/testdata/src/ping/ping.go b/testdata/src/ping/ping.go
index b8a5ea2..882840c 100644
--- a/testdata/src/ping/ping.go
+++ b/testdata/src/ping/ping.go
@@ -6,22 +6,18 @@
 
 	_ "v.io/core/veyron/profiles"
 	"v.io/core/veyron2"
-	"v.io/core/veyron2/rt"
 
 	"pingpong"
 )
 
 func main() {
-	runtime, err := rt.New()
-	if err != nil {
-		panic(err)
-	}
-	defer runtime.Cleanup()
-	ctx := runtime.NewContext()
+	ctx, shutdown := veyron2.InitForTest()
+	defer shutdown()
+
 	log := veyron2.GetLogger(ctx)
 
 	s := pingpong.PingPongClient("pingpong")
-	pong, err := s.Ping(runtime.NewContext(), "PING")
+	pong, err := s.Ping(ctx, "PING")
 	if err != nil {
 		log.Fatal("error pinging: ", err)
 	}