[SPARK-29725][SQL][TESTS] Add ThriftServerPageSuite

[shahidki31]

What changes were proposed in this pull request?

Added UT for the classes ThriftServerPage.scala and ThriftServerSessionPage.scala

Why are the changes needed?

Currently, there are no UTs for testing Thriftserver UI page

Does this PR introduce any user-facing change?

No

How was this patch tested?

UT

[SparkQA]

Test build #113280 has finished for PR 26403 at commit e0407d6.

• This patch fails Scala style tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• .doc(\"Comma-separated list of class names implementing \" +
• sealed abstract class PluginContainer
• class PluginMetricsSource(
• case class PluginMessage(pluginName: String, message: AnyRef)
• public class GangliaReporter extends ScheduledReporter
• public static class Builder
• abstract class IntervalNumOperation(
• case class MultiplyInterval(interval: Expression, num: Expression)
• case class DivideInterval(interval: Expression, num: Expression)
• case class AlterTableAddPartitionStatement(
• case class AlterTableSerDePropertiesStatement(
• case class ShowCurrentNamespaceStatement() extends ParsedStatement
• case class ShowCurrentNamespace(catalogManager: CatalogManager) extends Command
• case class ShowCurrentNamespaceExec(

[SparkQA]

Test build #113281 has finished for PR 26403 at commit e420857.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[shahidki31]

retest this please

[shahidki31]

cc @srowen Kindly review

[shahidki31]

Thanks @srowen for the review

[SparkQA]

Test build #113285 has finished for PR 26403 at commit e420857.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #113288 has finished for PR 26403 at commit d085611.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[HyukjinKwon]

Merged to master.

[shahidki31]

Thanks @HyukjinKwon @srowen