improve test queality

sql/hive/src/test/resources/golden/timestamp cast #3-0-89ef5480d0dd001cec4642de58f8632f

@@ -0,0 +1 @@
+1.0

sql/hive/src/test/resources/golden/timestamp cast #4-0-5a1f6c48122aae7d90b30df172fa9e5b

@@ -0,0 +1 @@
+-1.0

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveQuerySuite.scala

@@ -180,8 +180,7 @@ class HiveQuerySuite extends HiveComparisonTest with SQLTestUtils with BeforeAnd
     "SELECT CAST(CAST('NaN' AS DOUBLE) AS DECIMAL(1,1)) FROM src LIMIT 1")
 
   createQueryTest("constant null testing",
-    """set spark.sql.legacy.allowCastNumericToTimestamp=true;
-      | SELECT
+    """| SELECT
       |IF(FALSE, CAST(NULL AS STRING), CAST(1 AS STRING)) AS COL1,
       |IF(TRUE, CAST(NULL AS STRING), CAST(1 AS STRING)) AS COL2,
       |IF(FALSE, CAST(NULL AS INT), CAST(1 AS INT)) AS COL3,
@@ -202,13 +201,14 @@ class HiveQuerySuite extends HiveComparisonTest with SQLTestUtils with BeforeAnd
       |IF(TRUE, CAST(NULL AS BINARY), CAST("1" AS BINARY)) AS COL18,
       |IF(FALSE, CAST(NULL AS DATE), CAST("1970-01-01" AS DATE)) AS COL19,
       |IF(TRUE, CAST(NULL AS DATE), CAST("1970-01-01" AS DATE)) AS COL20,
-      |IF(TRUE, CAST(NULL AS TIMESTAMP), CAST(1 AS TIMESTAMP)) AS COL21,
+      |IF(TRUE, CAST(NULL AS TIMESTAMP), CAST('1969-12-31 16:00:01' AS TIMESTAMP)) AS COL21,
       |IF(FALSE, CAST(NULL AS DECIMAL), CAST(1 AS DECIMAL)) AS COL22,
       |IF(TRUE, CAST(NULL AS DECIMAL), CAST(1 AS DECIMAL)) AS COL23
       |FROM src LIMIT 1""".stripMargin)
 
   test("constant null testing timestamp") {
-    val r1 = sql("SELECT IF(FALSE, CAST(NULL AS TIMESTAMP), TIMESTAMP_SECONDS(1)) AS COL20")
+    val r1 = sql("SELECT IF(FALSE, CAST(NULL AS TIMESTAMP)," +
+      "CAST('1969-12-31 16:00:01' AS TIMESTAMP)) AS COL20")
       .collect().head
     assert(new Timestamp(1000) == r1.getTimestamp(0))
   }
@@ -564,14 +564,12 @@ class HiveQuerySuite extends HiveComparisonTest with SQLTestUtils with BeforeAnd
 
   createQueryTest("timestamp cast #3",
     """
-      |set spark.sql.legacy.allowCastNumericToTimestamp=true;
-      |SELECT CAST(CAST(1.2 AS TIMESTAMP) AS DOUBLE) FROM src LIMIT 1
+      |SELECT CAST(TIMESTAMP_SECONDS(CAST(1.2 AS INT)) AS DOUBLE) FROM src LIMIT 1
     """.stripMargin)
 
   createQueryTest("timestamp cast #4",
     """
-      |set spark.sql.legacy.allowCastNumericToTimestamp=true;
-      |SELECT CAST(CAST(-1.2 AS TIMESTAMP) AS DOUBLE) FROM src LIMIT 1
+      |SELECT CAST(TIMESTAMP_SECONDS(CAST(-1.2 AS INT)) AS DOUBLE) FROM src LIMIT 1
     """.stripMargin)
 
   test("timestamp cast #5") {