[KYUUBI #957] Reopen KyuubiServerSuite

<!--
Thanks for sending a pull request!

Here are some tips for you:
  1. If this is your first time, please read our contributor guidelines: https://kyuubi.readthedocs.io/en/latest/community/contributions.html
  2. If the PR is related to an issue in https://github.com/apache/incubator-kyuubi/issues, add '[KYUUBI #XXXX]' in your PR title, e.g., '[KYUUBI #XXXX] Your PR title ...'.
  3. If the PR is unfinished, add '[WIP]' in your PR title, e.g., '[WIP][KYUUBI #XXXX] Your PR title ...'.
-->

### _Why are the changes needed?_
<!--
Please clarify why the changes are needed. For instance,
  1. If you add a feature, you can talk about the use case of it.
  2. If you fix a bug, you can clarify why it is a bug.
-->

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [ ] [Run test](https://kyuubi.readthedocs.io/en/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #960 from yanghua/KYUUBI-957.

Closes #957

94cdddd [yanghua] [KYUUBI #957] Reopen KyuubiServerSuite

Authored-by: yanghua <yanghua1127@gmail.com>
Signed-off-by: Cheng Pan <chengpan@apache.org>
(cherry picked from commit 4aa93d3)
Signed-off-by: Cheng Pan <chengpan@apache.org>

kyuubi-server/src/test/scala/org/apache/kyuubi/server/KyuubiServerSuite.scala

@@ -23,7 +23,7 @@ import org.apache.kyuubi.service.ServiceState._
 
 class KyuubiServerSuite extends KyuubiFunSuite {
 
-  ignore("kyuubi server basic") {
+  test("kyuubi server basic") {
     val server = new KyuubiServer()
     server.stop()
     val conf = KyuubiConf().set(KyuubiConf.FRONTEND_BIND_PORT, 0)
@@ -35,7 +35,7 @@ class KyuubiServerSuite extends KyuubiFunSuite {
 
     server.initialize(conf)
     assert(server.getServiceState === INITIALIZED)
-    val backendService = server.getServices(1).asInstanceOf[KyuubiBackendService]
+    val backendService = server.getServices(2).asInstanceOf[KyuubiBackendService]
     assert(backendService.getServiceState == INITIALIZED)
     assert(backendService.getServices.forall(_.getServiceState === INITIALIZED))
     assert(server.connectionUrl.split(":").length === 2)
@@ -57,7 +57,7 @@ class KyuubiServerSuite extends KyuubiFunSuite {
     server.stop()
   }
 
-  ignore("invalid port") {
+  test("invalid port") {
     val conf = KyuubiConf().set(KyuubiConf.FRONTEND_BIND_PORT, 100)
     val e = intercept[KyuubiException](new KyuubiServer().initialize(conf))
     assert(e.getMessage.contains("Failed to initialize frontend service"))