[SPARK-17314][CORE] Use Netty's DefaultThreadFactory to enable its fa…

…st ThreadLocal impl

## What changes were proposed in this pull request?

When a thread is a Netty's FastThreadLocalThread, Netty will use its fast ThreadLocal implementation. It has a better performance than JDK's (See the benchmark results in netty/netty#4417, note: it's not a fix to Netty's FastThreadLocal. It just fixed an issue in Netty's benchmark codes)

This PR just changed the ThreadFactory to Netty's DefaultThreadFactory which will use FastThreadLocalThread. There is also a minor change to the thread names. See https://github.com/netty/netty/blob/netty-4.0.22.Final/common/src/main/java/io/netty/util/concurrent/DefaultThreadFactory.java#L94

## How was this patch tested?

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #14879 from zsxwing/netty-thread.

common/network-common/src/main/java/org/apache/spark/network/util/NettyUtils.java

@@ -20,7 +20,6 @@
 import java.lang.reflect.Field;
 import java.util.concurrent.ThreadFactory;
 
-import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import io.netty.buffer.PooledByteBufAllocator;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoopGroup;
@@ -31,6 +30,7 @@
 import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
+import io.netty.util.concurrent.DefaultThreadFactory;
 import io.netty.util.internal.PlatformDependent;
 
 /**
@@ -39,10 +39,7 @@
 public class NettyUtils {
   /** Creates a new ThreadFactory which prefixes each thread with the given name. */
   public static ThreadFactory createThreadFactory(String threadPoolPrefix) {
-    return new ThreadFactoryBuilder()
-      .setDaemon(true)
-      .setNameFormat(threadPoolPrefix + "-%d")
-      .build();
+    return new DefaultThreadFactory(threadPoolPrefix, true);
   }
 
   /** Creates a Netty EventLoopGroup based on the IOMode. */