[SPARK-19607][HOTFIX] Finding QueryExecution that matches provided executionId

## What changes were proposed in this pull request?

apache#16940 adds a test case which does not stop the spark job. It causes many failures of other test cases.

- https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.7/2403/consoleFull
- https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-maven-hadoop-2.7/2600/consoleFull

```
[info]   org.apache.spark.SparkException: Only one SparkContext may be running in this JVM (see SPARK-2243). To ignore this error, set spark.driver.allowMultipleContexts = true. The currently running SparkContext was created at:
```

## How was this patch tested?

Pass the Jenkins test.

Author: Dongjoon Hyun <[email protected]>

Closes apache#16943 from dongjoon-hyun/SPARK-19607-2.

Author: dongjoon-hyun

sql/core/src/test/scala/org/apache/spark/sql/execution/SQLExecutionSuite.scala

@@ -129,6 +129,8 @@ class SQLExecutionSuite extends SparkFunSuite {
     df.collect()
 
     assert(df.queryExecution === queryExecution)
+
+    spark.stop()
   }
 }