Bringing a node manager down blocks restart of LLAP service

For YARN service, when number of running instances != number of desired instances, the service state may be in STARTED or FLEX (instead of STABLE). For Hive LLAP side, there is a config to control the threshold of service health check. The Hive LLAP code misses checking these states, which can result in the service not coming up even if the threshold is met.
https://github.com/apache/hive/blob/master/llap-server/src/java/org/apache/hadoop/hive/llap/cli/status/LlapStatusServiceDriver.java#L382