Update SparkSession.scala

Author: AngersZhuuuu

sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala

@@ -600,6 +600,7 @@ class SparkSession private(
    * @since 2.0.0
    */
   def sql(sqlText: String): DataFrame = {
+    SparkSession.setActiveSession(this)
     val tracker = new QueryPlanningTracker
     val plan = tracker.measurePhase(QueryPlanningTracker.PARSING) {
       sessionState.sqlParser.parsePlan(sqlText)