[SPARK-26607][SQL][TEST] Remove Spark 2.2.x testing from HiveExternal…

…CatalogVersionsSuite

## What changes were proposed in this pull request?

The vote of final release of `branch-2.2` passed and the branch goes EOL. This PR removes Spark 2.2.x from the testing coverage.

## How was this patch tested?

Pass the Jenkins.

Closes #23526 from dongjoon-hyun/SPARK-26607.

Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
(cherry picked from commit 3587a9a)
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>

sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveExternalCatalogVersionsSuite.scala

@@ -203,7 +203,7 @@ class HiveExternalCatalogVersionsSuite extends SparkSubmitTestUtils {
 
 object PROCESS_TABLES extends QueryTest with SQLTestUtils {
   // Tests the latest version of every release line.
-  val testingVersions = Seq("2.2.2", "2.3.2", "2.4.0")
+  val testingVersions = Seq("2.3.2", "2.4.0")
 
   protected var spark: SparkSession = _