- [x] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.
- [x] I have checked the [FAQ](https://github.com/apache/dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: master
* Operating System version: all platform
* Java version: all version

### Steps to reproduce this issue

1. set SystemProperty "java.net.preferIPv6Addresses" to true.
2. call org.apache.dubbo.common.utils.NetUtils#isPreferIPV6Address().
3. check the return value.

### Expected Result

org.apache.dubbo.common.utils.NetUtils#isPreferIPV6Address() will return true when SystemProperty "java.net.preferIPv6Addresses" set to true.

### Actual Result

org.apache.dubbo.common.utils.NetUtils#isPreferIPV6Address() method ignore SystemProperty "java.net.preferIPv6Addresses" and always return false
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