[SPARK-15618][SQL][MLLIB] Use SparkSession.builder.sparkContext if applicable.

## What changes were proposed in this pull request?

This PR changes function `SparkSession.builder.sparkContext(..)` from **private[sql]** into **private[spark]**, and uses it if applicable like the followings.
```
- val spark = SparkSession.builder().config(sc.getConf).getOrCreate()
+ val spark = SparkSession.builder().sparkContext(sc).getOrCreate()
```

## How was this patch tested?

Pass the existing Jenkins tests.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #13365 from dongjoon-hyun/SPARK-15618.

4 files changed, 9 insertions, 11 deletions

diff --git a/mllib/src/test/scala/org/apache/spark/ml/feature/ChiSqSelectorSuite.scala b/mllib/src/test/scala/org/apache/spark/ml/feature/ChiSqSelectorSuite.scala
index 40d5b4881f..3558290b23 100644
--- a/mllib/src/test/scala/org/apache/spark/ml/feature/ChiSqSelectorSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/ml/feature/ChiSqSelectorSuite.scala
@@ -23,18 +23,14 @@ import org.apache.spark.ml.util.{DefaultReadWriteTest, MLTestingUtils}
 import org.apache.spark.ml.util.TestingUtils._
 import org.apache.spark.mllib.feature
 import org.apache.spark.mllib.util.MLlibTestSparkContext
-import org.apache.spark.sql.{Row, SparkSession}
+import org.apache.spark.sql.Row
 
 class ChiSqSelectorSuite extends SparkFunSuite with MLlibTestSparkContext
   with DefaultReadWriteTest {
 
   test("Test Chi-Square selector") {
-    val spark = SparkSession.builder
-      .master("local[2]")
-      .appName("ChiSqSelectorSuite")
-      .getOrCreate()
+    val spark = this.spark
     import spark.implicits._
-
     val data = Seq(
       LabeledPoint(0.0, Vectors.sparse(3, Array((0, 8.0), (1, 7.0)))),
       LabeledPoint(1.0, Vectors.sparse(3, Array((1, 9.0), (2, 6.0)))),
diff --git a/mllib/src/test/scala/org/apache/spark/ml/feature/QuantileDiscretizerSuite.scala b/mllib/src/test/scala/org/apache/spark/ml/feature/QuantileDiscretizerSuite.scala
index 621c13a8e5..b73dbd6232 100644
--- a/mllib/src/test/scala/org/apache/spark/ml/feature/QuantileDiscretizerSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/ml/feature/QuantileDiscretizerSuite.scala
@@ -27,7 +27,7 @@ class QuantileDiscretizerSuite
   extends SparkFunSuite with MLlibTestSparkContext with DefaultReadWriteTest {
 
   test("Test observed number of buckets and their sizes match expected values") {
-    val spark = SparkSession.builder().config(sc.getConf).getOrCreate()
+    val spark = this.spark
     import spark.implicits._
 
     val datasetSize = 100000
@@ -53,7 +53,7 @@ class QuantileDiscretizerSuite
   }
 
   test("Test transform method on unseen data") {
-    val spark = SparkSession.builder().config(sc.getConf).getOrCreate()
+    val spark = this.spark
     import spark.implicits._
 
     val trainDF = sc.parallelize(1.0 to 100.0 by 1.0).map(Tuple1.apply).toDF("input")
@@ -82,7 +82,7 @@ class QuantileDiscretizerSuite
   }
 
   test("Verify resulting model has parent") {
-    val spark = SparkSession.builder().config(sc.getConf).getOrCreate()
+    val spark = this.spark
     import spark.implicits._
 
     val df = sc.parallelize(1 to 100).map(Tuple1.apply).toDF("input")
diff --git a/mllib/src/test/scala/org/apache/spark/ml/recommendation/ALSSuite.scala b/mllib/src/test/scala/org/apache/spark/ml/recommendation/ALSSuite.scala
index 59b5edc401..e8ed50acf8 100644
--- a/mllib/src/test/scala/org/apache/spark/ml/recommendation/ALSSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/ml/recommendation/ALSSuite.scala
@@ -591,6 +591,7 @@ class ALSCleanerSuite extends SparkFunSuite {
         val spark = SparkSession.builder
           .master("local[2]")
           .appName("ALSCleanerSuite")
+          .sparkContext(sc)
           .getOrCreate()
         import spark.implicits._
         val als = new ALS()
@@ -606,7 +607,7 @@ class ALSCleanerSuite extends SparkFunSuite {
         val pattern = "shuffle_(\\d+)_.+\\.data".r
         val rddIds = resultingFiles.flatMap { f =>
           pattern.findAllIn(f.getName()).matchData.map { _.group(1) } }
-        assert(rddIds.toSet.size === 4)
+        assert(rddIds.size === 4)
       } finally {
         sc.stop()
       }
diff --git a/mllib/src/test/scala/org/apache/spark/ml/tree/impl/TreeTests.scala b/mllib/src/test/scala/org/apache/spark/ml/tree/impl/TreeTests.scala
index 8cbd652bac..d2fa8d0d63 100644
--- a/mllib/src/test/scala/org/apache/spark/ml/tree/impl/TreeTests.scala
+++ b/mllib/src/test/scala/org/apache/spark/ml/tree/impl/TreeTests.scala
@@ -42,9 +42,10 @@ private[ml] object TreeTests extends SparkFunSuite {
       data: RDD[LabeledPoint],
       categoricalFeatures: Map[Int, Int],
       numClasses: Int): DataFrame = {
-    val spark = SparkSession.builder
+    val spark = SparkSession.builder()
       .master("local[2]")
       .appName("TreeTests")
+      .sparkContext(data.sparkContext)
       .getOrCreate()
     import spark.implicits._