When I used the SaveService. loadTree API of jmeter, I found that if there is a View Results Tree in the jmx script, the generated HashTree key is null

### Expected behavior

I would like to know how to use Jmeter's API correctly. Convert jmx to hashTree.

### Actual behavior

_No response_

### Steps to reproduce the problem

When I used the SaveService. loadTree API of jmeter, I found that if there is a View Results Tree in the jmx script, the generated HashTree key is null
jmx script as follows

```xml

false
true
false







continue

false
2

3
1
false


true










${ip}
GET
true
false
true
false













www.aa.com
GET
true
false
true
false






false

saveConfig

true
true
true
true
true
true
true
true
true
false
true
true
false
false
false
true
false
false
false
true
0
true
true
true
true
true
true






false

saveConfig

true
true
true
true
true
true
true
true
true
false
true
true
false
false
false
true
false
false
false
true
0
true
true
true
true
true
true






import java.util.Properties;
Properties properties=System.getProperties();
for(Object key:properties.keySet()){
log.info(key+"=>"+properties.getProperty(key+""));
}


false






ip
https://www.baidu.com
=





false

saveConfig

true
true
true
true
true
true
true
true
true
false
true
true
false
false
false
true
false
false
false
true
0
true
true
true
true
true
true






false

saveConfig

true
true
true
true
true
true
true
true
true
false
true
true
false
false
false
true
false
false
false
true
0
true
true
true
true
true
true






false

saveConfig

true
true
true
true
true
true
true
true
true
false
true
true
false
false
false
true
false
false
false
true
0
true
true
true
true
true
true

```

### JMeter Version

5.5

### Java Version

_No response_

### OS Version

_No response_