[Bug] 1.5.0 mysql backend内存泄漏

### Bug Type (问题类型)

performance (性能下降)

### Before submit

- [x] 我已经确认现有的 [Issues](https://github.com/apache/hugegraph/issues) 与 [FAQ](https://hugegraph.apache.org/docs/guides/faq/) 中没有相同 / 重复问题 (I have confirmed and searched that there are no similar problems in the historical issue and documents)

### Environment (环境信息)

- Server Version: 1.5.0 (Apache Release Version)
- Backend: Mysql
- OS: CentOS 7.x

### Expected & Actual behavior (期望与实际表现)

- 问题描述：
1、内存dump中mysql驱动实例呈线性增长趋势
2、gc回收后占用空间没有下降，直至内存溢出
- 问题分析
在ResultSetWrapper中创建和close方法中分别加入日志，发现存在一定比例的ResultSetWrapper没有正常调用关闭方法。
- 问题解决
在ResultSetWrapper中加入finalize方法，在回收前判断resultSet和statement有没有正常关闭，未关闭则处理
加入此处理后问题解决。
@Override
protected void finalize() {
try {
if (this.resultSet != null && !this.resultSet.isClosed()) {
LOG.warn("resultSet was not closed properly, forcing close via finalize");
this.resultSet.close();
}
} catch (SQLException e) {
throw new BackendException("Failed to close ResultSet", e);
} finally {
try {
if (this.statement != null && !this.statement.isClosed()) {
LOG.warn("statement was not closed properly, forcing close via finalize");
this.statement.close();
}
} catch (SQLException e) {
throw new BackendException("Failed to close Statement", e);
}
}
}

### Vertex/Edge example (问题点 / 边数据举例)

```javascript

```

### Schema [VertexLabel, EdgeLabel, IndexLabel] (元数据结构)

```javascript

```

Search the Java codebase for ResultSetWrapper and inspect how its resultSet and statement are created, used, and closed. Reproduce the MySQL backend workload on version 1.5.0 while checking logs or a memory dump, then verify that resources are released consistently and memory no longer grows until exhaustion.

Written by the indexing model from the issue text.