定时刷新TableMeta缓存的功能失效了

[wuwen5]

• I have searched the issues of this repository and believe that this is not a duplicate.

Ⅰ. Issue Description

定时刷新TableMeta缓存的功能失效了，程序每900秒后会由业务调用主动查询一次tableMeta导致慢请求
1.7.0 版本之后没有定时任务发起tableMetaRefreshEvent事件,导致tableMetaRefresh会一直处于tableMetaRefreshQueue.take()状态。

在https://github.com/apache/incubator-seata/pull/4734/files 这次更新之后，原60秒刷新一次tablemeta缓存的功能失效了。

Ⅱ. Describe what happened

If there is an exception, please attach the exception trace:

Just paste your stack trace here!

Ⅲ. Describe what you expected to happen

Ⅳ. How to reproduce it (as minimally and precisely as possible)

1. xxx
2. xxx
3. xxx

Minimal yet complete reproducer code (or URL to code):

Ⅴ. Anything else we need to know?

Ⅵ. Environment:

• JDK version(e.g. java -version):
• Seata client/server version:
• Database version:
• OS(e.g. uname -a):
• Others:

[funky-eyes]

TableMetaCacheFactory#tableMetaRefreshEvent
And 119 lines, the refresh task will be initiated actively after the refresh time is reached

            tableMetaRefreshExecutor.execute(() -> {
                while (true) {
                    // 1. check table meta
                    if (ENABLE_TABLE_META_CHECKER_ENABLE
                        && System.currentTimeMillis() - lastRefreshFinishTime > TABLE_META_CHECKER_INTERVAL) {
                        tableMetaRefreshEvent(dataSource.getResourceId());
                    }

[funky-eyes]

我明白你的意思了，由于这俩逻辑在同一个线程里，所以上面的刷新失效了
I see what you mean. Since these two logics are in the same thread, the above refresh is invalid.

[funky-eyes]

你可以提交一个pr来修复这个bug吗？
Can you commit a PR to fix this bug?