private ServerCrashProcedure getSCPForServer(ServerName serverName) throws IOException {
    return UTIL.getMiniHBaseCluster().getMaster().getProcedures().stream()
      .filter(p -> p instanceof ServerCrashProcedure).map(p -> (ServerCrashProcedure) p)
      .filter(p -> p.getServerName().equals(serverName)).findFirst().orElse(null);
  }
SCP does not support rollback actually, here we just want to simulate that when there is a code
bug, SCP and its sub procedures will not hang there forever, and it will not mess up the
procedure store.
hbase-server/src/test/java/org/apache/hadoop/hbase/master/assignment/TestRollbackSCP.java