[SPARK-11624][SPARK-11972][SQL] fix commands that need hive to exec

In SparkSQLCLI, we have created a `CliSessionState`, but then we call `SparkSQLEnv.init()`, which will start another `SessionState`. This would lead to exception because `processCmd` need to get the `CliSessionState` instance by calling `SessionState.get()`, but the return value would be a instance of `SessionState`. See the exception below.

spark-sql> !echo "test";
Exception in thread "main" java.lang.ClassCastException: org.apache.hadoop.hive.ql.session.SessionState cannot be cast to org.apache.hadoop.hive.cli.CliSessionState
	at org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:112)
	at org.apache.spark.sql.hive.thriftserver.SparkSQLCLIDriver.processCmd(SparkSQLCLIDriver.scala:301)
	at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:376)
	at org.apache.spark.sql.hive.thriftserver.SparkSQLCLIDriver$.main(SparkSQLCLIDriver.scala:242)
	at org.apache.spark.sql.hive.thriftserver.SparkSQLCLIDriver.main(SparkSQLCLIDriver.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:691)
	at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:180)
	at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:205)
	at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:120)
	at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #9589 from adrian-wang/clicommand.