Revert "[Spark-3490] Disable SparkUI for tests"

core/src/main/scala/org/apache/spark/SparkContext.scala

...ark/scheduler/cluster/CoarseGrainedSchedulerBackend.scala

...apache/spark/scheduler/cluster/SimrSchedulerBackend.scala

...spark/scheduler/cluster/SparkDeploySchedulerBackend.scala

core/src/test/scala/org/apache/spark/ui/UISuite.scala

pom.xml

project/SparkBuild.scala

...n/scala/org/apache/spark/streaming/StreamingContext.scala

...in/scala/org/apache/spark/streaming/StreamingSource.scala

...in/scala/org/apache/spark/streaming/ui/StreamingTab.scala

...g/src/test/scala/org/apache/spark/streaming/UISuite.scala

...cala/org/apache/spark/deploy/yarn/ApplicationMaster.scala

.../spark/scheduler/cluster/YarnClientSchedulerBackend.scala