[SPARK-20557][SQL] Support for db column type TIMESTAMP WITH TIME ZONE

## What changes were proposed in this pull request?

SparkSQL can now read from a database table with column type [TIMESTAMP WITH TIME ZONE](https://docs.oracle.com/javase/8/docs/api/java/sql/Types.html#TIMESTAMP_WITH_TIMEZONE).

## How was this patch tested?

Tested against Oracle database.

JoshRosen, you seem to know the class, would you look at this? Thanks!

Author: Jannik Arndt <jannik@jannikarndt.de>

Closes #17832 from JannikArndt/spark-20557-timestamp-with-timezone.

external/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/OracleIntegrationSuite.scala

@@ -70,6 +70,12 @@ class OracleIntegrationSuite extends DockerJDBCIntegrationSuite with SharedSQLCo
       """.stripMargin.replaceAll("\n", " ")).executeUpdate()
     conn.commit()
 
+    conn.prepareStatement("CREATE TABLE ts_with_timezone (id NUMBER(10), t TIMESTAMP WITH TIME ZONE)")
+        .executeUpdate()
+    conn.prepareStatement("INSERT INTO ts_with_timezone VALUES (1, to_timestamp_tz('1999-12-01 11:00:00 UTC','YYYY-MM-DD HH:MI:SS TZR'))")
+        .executeUpdate()
+    conn.commit()
+
     sql(
       s"""
         |CREATE TEMPORARY VIEW datetime
@@ -185,4 +191,11 @@ class OracleIntegrationSuite extends DockerJDBCIntegrationSuite with SharedSQLCo
     sql("INSERT INTO TABLE datetime1 SELECT * FROM datetime where id = 1")
     checkRow(sql("SELECT * FROM datetime1 where id = 1").head())
   }
+
+  test("SPARK-20557: column type TIMEZONE with TIME STAMP should be recognized") {
+    val dfRead = sqlContext.read.jdbc(jdbcUrl, "ts_with_timezone", new Properties)
+    val rows = dfRead.collect()
+    val types = rows(0).toSeq.map(x => x.getClass.toString)
+    assert(types(1).equals("class java.sql.Timestamp"))
+  }
 }

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JdbcUtils.scala

@@ -223,6 +223,9 @@ object JdbcUtils extends Logging {
       case java.sql.Types.STRUCT        => StringType
       case java.sql.Types.TIME          => TimestampType
       case java.sql.Types.TIMESTAMP     => TimestampType
+      case java.sql.Types.TIMESTAMP_WITH_TIMEZONE
+                                        => TimestampType
+      case -101                         => TimestampType // Value for Timestamp with Time Zone in Oracle
       case java.sql.Types.TINYINT       => IntegerType
       case java.sql.Types.VARBINARY     => BinaryType
       case java.sql.Types.VARCHAR       => StringType