[SPARK-25670][TEST] Reduce number of tested timezones in JsonExpressionsSuite

## What changes were proposed in this pull request?

After the changes, total execution time of `JsonExpressionsSuite.scala` dropped from 12.5 seconds to 3 seconds.

Closes #22657 from MaxGekk/json-timezone-test.

Authored-by: Maxim Gekk <maxim.gekk@databricks.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>

Author: MaxGekk

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/JsonExpressionsSuite.scala

@@ -23,7 +23,7 @@ import org.apache.spark.SparkFunSuite
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.errors.TreeNodeException
 import org.apache.spark.sql.catalyst.plans.PlanTestBase
-import org.apache.spark.sql.catalyst.util.{ArrayBasedMapData, DateTimeTestUtils, DateTimeUtils, GenericArrayData, PermissiveMode}
+import org.apache.spark.sql.catalyst.util._
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.types._
 import org.apache.spark.unsafe.types.UTF8String
@@ -510,7 +510,7 @@ class JsonExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper with
     )
 
     val jsonData2 = """{"t": "2016-01-01T00:00:00"}"""
-    for (tz <- DateTimeTestUtils.ALL_TIMEZONES) {
+    for (tz <- DateTimeTestUtils.outstandingTimezones) {
       c = Calendar.getInstance(tz)
       c.set(2016, 0, 1, 0, 0, 0)
       c.set(Calendar.MILLISECOND, 0)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/DateTimeTestUtils.scala

@@ -26,6 +26,16 @@ object DateTimeTestUtils {
 
   val ALL_TIMEZONES: Seq[TimeZone] = TimeZone.getAvailableIDs.toSeq.map(TimeZone.getTimeZone)
 
+  val outstandingTimezones: Seq[TimeZone] = Seq(
+    "UTC",
+    "PST",
+    "CET",
+    "Africa/Dakar",
+    "America/Los_Angeles",
+    "Antarctica/Vostok",
+    "Asia/Hong_Kong",
+    "Europe/Amsterdam").map(TimeZone.getTimeZone)
+
   def withDefaultTimeZone[T](newDefaultTimeZone: TimeZone)(block: => T): T = {
     val originalDefaultTimeZone = TimeZone.getDefault
     try {