[KYUUBI #1972] Fix flaky test: SchedulerPoolSuite: Scheduler pool

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### _Why are the changes needed?_
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close #1972

### _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.apache.org/docs/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #1982 from wForget/KYUUBI-1972.

Closes #1972

2d83b24 [Wang Zhen] [KYUUBI-1972] Fix flaky test: SchedulerPoolSuite: Scheduler pool

Authored-by: Wang Zhen <wangzhen07@qiyi.com>
Signed-off-by: ulysses-you <ulyssesyou@apache.org>

Author: wForget

externals/kyuubi-spark-sql-engine/src/test/scala/org/apache/kyuubi/engine/spark/SchedulerPoolSuite.scala

@@ -96,7 +96,7 @@ class SchedulerPoolSuite extends WithSparkSQLEngine with HiveJDBCTestHelper {
         })
       }
       threads.shutdown()
-      eventually(Timeout(10.seconds)) {
+      eventually(Timeout(20.seconds)) {
         // We can not ensure that job1 is started before job2 so here using abs.
         assert(Math.abs(job1StartTime - job2StartTime) < 1000)
         // Job1 minShare is 2(total resource) so that job2 should be allocated tasks after