Fix flaky test TestLockManager

When the LockProcedure was scheduled. It will called TimeoutExecutorThread#add method.

public void add(Procedure<TEnvironment> procedure) {
  assert procedure.getState() == ProcedureState.WAITING_TIMEOUT;
  LOG.info("ADDED {}; timeout={}, timestamp={}", procedure, procedure.getTimeout(),
    procedure.getTimeoutTimestamp());
  queue.add(new DelayedProcedure<>(procedure));
}

But LockProcedure's unlock method may called before it was scheduled. And it will change the state to RUNNABLE. This will make the assert error.

// Can be called before procedure gets scheduled, in which case, the execute() will finish
// immediately and release the underlying locks.
public void unlock(final MasterProcedureEnv env) {
  unlock.set(true);
  locked.set(false);
  // Maybe timeout already awakened the event and the procedure has finished.
  synchronized (event) {
    if (!event.isReady()) {
      LOG.info("Update procedure {} state to RUNNABLE", this);
      setState(ProcedureProtos.ProcedureState.RUNNABLE);
      event.wake(env.getProcedureScheduler());
    }
  }
}

I added log in these methods.

2019-05-28 15:34:16,179 INFO [Time-limited test] locking.LockProcedure(223): Update procedure pid=21, state=WAITING_TIMEOUT, locked=true; org.apache.hadoop.hbase.master.locking.LockProcedure, tableName=namespace:table, type=EXCLUSIVE state to RUNNABLE
2019-05-28 15:34:16,179 DEBUG [Time-limited test] procedure.MasterProcedureScheduler(352): Add TableQueue(namespace:table, xlock=true (21) sharedLock=0 size=1) to run queue because: pid=21, state=RUNNABLE, locked=true; org.apache.hadoop.hbase.master.locking.LockProcedure, tableName=namespace:table, type=EXCLUSIVE has lock
2019-05-28 15:34:16,179 INFO [PEWorker-1] procedure2.ProcedureExecutor$WorkerThread(1967): ASSERT pid=21
java.lang.AssertionError
at org.apache.hadoop.hbase.procedure2.TimeoutExecutorThread.add(TimeoutExecutorThread.java:82)
at org.apache.hadoop.hbase.procedure2.ProcedureExecutor.execProcedure(ProcedureExecutor.java:1690)
at org.apache.hadoop.hbase.procedure2.ProcedureExecutor.executeProcedure(ProcedureExecutor.java:1395)
at org.apache.hadoop.hbase.procedure2.ProcedureExecutor.access$1100(ProcedureExecutor.java:78)
at org.apache.hadoop.hbase.procedure2.ProcedureExecutor$WorkerThread.run(ProcedureExecutor.java:1965)