potential thread-unsafe problem in server-alarm-plugin of oap-server module

[liuhaoXD]

skywalking/oap-server/server-alarm-plugin/src/main/java/org/apache/skywalking/oap/server/core/alarm/provider/RunningRule.java

Line 232 in f9cf17b

int minutes = Minutes.minutesBetween(timebucket, endTime).getMinutes();

• this.moveTo()at line 234 is thread-unsafe.
• minutesBetween operation should be protected by lock()
• if statement at line 233 is duplicate with line 240

[wu-sheng]

Could you submit the issue in English or send a pull request to fix the issue?