[SQL][MINOR][TEST] Set spark.unsafe.exceptionOnMemoryLeak to true

## What changes were proposed in this pull request?
When running IntelliJ, we are unable to capture the exception of memory leak detection.
> org.apache.spark.executor.Executor: Managed memory leak detected

Explicitly setting `spark.unsafe.exceptionOnMemoryLeak` in SparkConf when building the SparkSession, instead of reading it from system properties.

## How was this patch tested?
N/A

Author: gatorsmile <gatorsmile@gmail.com>

Closes #18967 from gatorsmile/setExceptionOnMemoryLeak.

sql/core/src/test/scala/org/apache/spark/sql/test/SharedSQLContext.scala

@@ -31,7 +31,9 @@ import org.apache.spark.sql.{SparkSession, SQLContext}
 trait SharedSQLContext extends SQLTestUtils with BeforeAndAfterEach with Eventually {
 
   protected def sparkConf = {
-    new SparkConf().set("spark.hadoop.fs.file.impl", classOf[DebugFilesystem].getName)
+    new SparkConf()
+      .set("spark.hadoop.fs.file.impl", classOf[DebugFilesystem].getName)
+      .set("spark.unsafe.exceptionOnMemoryLeak", "true")
   }
 
   /**

sql/hive/src/main/scala/org/apache/spark/sql/hive/test/TestHive.scala

@@ -55,7 +55,8 @@ object TestHive
           "org.apache.spark.sql.hive.execution.PairSerDe")
         .set("spark.sql.warehouse.dir", TestHiveContext.makeWarehouseDir().toURI.getPath)
         // SPARK-8910
-        .set("spark.ui.enabled", "false")))
+        .set("spark.ui.enabled", "false")
+        .set("spark.unsafe.exceptionOnMemoryLeak", "true")))
 
 
 case class TestHiveVersion(hiveClient: HiveClient)