[WIP] FIx flaky test in ConnectionLevelSparkEngineSuite

[ulysses-you]

❨?❩

Why are the changes needed?

How was this patch tested?

[codecov]

Codecov Report

Merging #395 (e8bdd4d) into master (2e33158) will increase coverage by 0.27%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #395      +/-   ##
==========================================
+ Coverage   80.49%   80.77%   +0.27%     
==========================================
  Files         101      101              
  Lines        3641     3652      +11     
  Branches      428      434       +6     
==========================================
+ Hits         2931     2950      +19     
+ Misses        492      484       -8     
  Partials      218      218              

Impacted Files	Coverage Δ
...ache/kyuubi/ha/client/EngineServiceDiscovery.scala	0.00% <0.00%> (ø)
.../engine/spark/session/SparkSQLSessionManager.scala	80.43% <0.00%> (-6.67%)	⬇️
...main/scala/org/apache/kyuubi/session/package.scala	0.00% <0.00%> (ø)
...ache/kyuubi/engine/spark/SparkProcessBuilder.scala	89.33% <0.00%> (+1.99%)	⬆️
...org/apache/kyuubi/operation/ExecuteStatement.scala	74.32% <0.00%> (+6.75%)	⬆️
.../org/apache/kyuubi/session/KyuubiSessionImpl.scala	77.52% <0.00%> (+7.52%)	⬆️

[ulysses-you]

seems it's a small bug, now the test is stable. cc @yaooqinn

[ulysses-you]

merging to master for 1.1.0

[yaooqinn]

I ignored the test in a previous PR