Use same pid file name for both active server and standby server

[PHILO-HE]

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[PHILO-HE]

In #2027, different pid file name (SmartSever.pid, Standby.pid) is used to support running active and standby server on a single node to facilitate debugging. However, suppose an active server halts, a standby server will transform its role to active server. On previous active server, a new standby server may be launched to recover the HA ability. When user tries to shut down the cluster, the new standby server cannot be killed since the stop script cannot distinguish active server and standby server. Instead, it always assumes the first configured server is active and pick up the pid from corresponding pid file. Thus, the new standby server is viewed as active server, but its pid is stored in Standby.pid.

Here, it is proposed that a consistent pid file name is used for both active server and standby server. Developer can use a dedicated node to debug standby server with start-standby.server.sh.