为什么同步代码块升级到轻量级锁，而不是偏向锁了呢

按照如下代码进行测试，理论上同步代码块里应该对对象添加偏向锁，可是为什么从输出上来看，添加的是轻量锁呢

java 版本 1.8.0_192-b12

	public static void test(){
		Object o = new Object();
		System.out.println(ClassLayout.parseInstance(o).toPrintable());
		synchronized (o){
			System.out.println(ClassLayout.parseInstance(o).toPrintable());
		}
		System.out.println(ClassLayout.parseInstance(o).toPrintable());
	}

java.lang.Object object internals:
 OFFSET  SIZE   TYPE DESCRIPTION                               VALUE
      0     4        (object header)                           01 00 00 00 (00000001 00000000 00000000 00000000) (1)
      4     4        (object header)                           00 00 00 00 (00000000 00000000 00000000 00000000) (0)
      8     4        (object header)                           e5 01 00 f8 (11100101 00000001 00000000 11111000) (-134217243)


java.lang.Object object internals:
 OFFSET  SIZE   TYPE DESCRIPTION                               VALUE
      0     4        (object header)                           b0 f4 70 01 (10110000 11110100 01110000 00000001) (24179888)
      4     4        (object header)                           00 00 00 00 (00000000 00000000 00000000 00000000) (0)
      8     4        (object header)                           e5 01 00 f8 (11100101 00000001 00000000 11111000) (-134217243)


java.lang.Object object internals:
 OFFSET  SIZE   TYPE DESCRIPTION                               VALUE
      0     4        (object header)                           01 00 00 00 (00000001 00000000 00000000 00000000) (1)
      4     4        (object header)                           00 00 00 00 (00000000 00000000 00000000 00000000) (0)
      8     4        (object header)                           e5 01 00 f8 (11100101 00000001 00000000 11111000) (-134217243)