[SPARK-21832][TEST] Merge SQLBuilderTest into ExpressionSQLBuilderSuite

## What changes were proposed in this pull request?

After [SPARK-19025](https://github.com/apache/spark/pull/16869), there is no need to keep SQLBuilderTest.
ExpressionSQLBuilderSuite is the only place to use it.
This PR aims to remove SQLBuilderTest.

## How was this patch tested?

Pass the updated `ExpressionSQLBuilderSuite`.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #19044 from dongjoon-hyun/SPARK-21832.

sql/hive/src/test/scala/org/apache/spark/sql/catalyst/ExpressionSQLBuilderSuite.scala

@@ -19,12 +19,29 @@ package org.apache.spark.sql.catalyst
 
 import java.sql.Timestamp
 
+import org.apache.spark.sql.QueryTest
 import org.apache.spark.sql.catalyst.dsl.expressions._
-import org.apache.spark.sql.catalyst.expressions.{If, Literal, SpecifiedWindowFrame, TimeAdd,
-  TimeSub, WindowSpecDefinition}
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.hive.test.TestHiveSingleton
 import org.apache.spark.unsafe.types.CalendarInterval
 
-class ExpressionSQLBuilderSuite extends SQLBuilderTest {
+class ExpressionSQLBuilderSuite extends QueryTest with TestHiveSingleton {
+  protected def checkSQL(e: Expression, expectedSQL: String): Unit = {
+    val actualSQL = e.sql
+    try {
+      assert(actualSQL == expectedSQL)
+    } catch {
+      case cause: Throwable =>
+        fail(
+          s"""Wrong SQL generated for the following expression:
+             |
+             |${e.prettyName}
+             |
+             |$cause
+           """.stripMargin)
+    }
+  }
+
   test("literal") {
     checkSQL(Literal("foo"), "'foo'")
     checkSQL(Literal("\"foo\""), "'\"foo\"'")

sql/hive/src/test/scala/org/apache/spark/sql/catalyst/SQLBuilderTest.scala

-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.spark.sql.catalyst
-
-import scala.util.control.NonFatal
-
-import org.apache.spark.sql.{DataFrame, Dataset, QueryTest}
-import org.apache.spark.sql.catalyst.expressions.Expression
-import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan
-import org.apache.spark.sql.hive.test.TestHiveSingleton
-
-
-abstract class SQLBuilderTest extends QueryTest with TestHiveSingleton {
-  protected def checkSQL(e: Expression, expectedSQL: String): Unit = {
-    val actualSQL = e.sql
-    try {
-      assert(actualSQL === expectedSQL)
-    } catch {
-      case cause: Throwable =>
-        fail(
-          s"""Wrong SQL generated for the following expression:
-             |
-             |${e.prettyName}
-             |
-             |$cause
-           """.stripMargin)
-    }
-  }
-}