[SPARK-26256][K8S] Fix labels for pod deletion

## What changes were proposed in this pull request?
Adds proper labels when deleting executor pods.

## How was this patch tested?
Manually with tests.

Closes apache#23209 from skonto/fix-deletion-labels.

Authored-by: Stavros Kontopoulos <[email protected]>
Signed-off-by: Marcelo Vanzin <[email protected]>

Author: Stavros Kontopoulos

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/ExecutorPodsAllocator.scala

@@ -93,6 +93,8 @@ private[spark] class ExecutorPodsAllocator(
           Utils.tryLogNonFatalError {
             kubernetesClient
               .pods()
+              .withLabel(SPARK_APP_ID_LABEL, applicationId)
+              .withLabel(SPARK_ROLE_LABEL, SPARK_POD_EXECUTOR_ROLE)
               .withLabel(SPARK_EXECUTOR_ID_LABEL, execId.toString)
               .delete()
           }

resource-managers/kubernetes/core/src/test/scala/org/apache/spark/scheduler/cluster/k8s/ExecutorPodsAllocatorSuite.scala

@@ -138,7 +138,15 @@ class ExecutorPodsAllocatorSuite extends SparkFunSuite with BeforeAndAfter {
     snapshotsStore.notifySubscribers()
     snapshotsStore.replaceSnapshot(Seq.empty[Pod])
     waitForExecutorPodsClock.setTime(podCreationTimeout + 1)
-    when(podOperations.withLabel(SPARK_EXECUTOR_ID_LABEL, "1")).thenReturn(labeledPods)
+    when(podOperations
+      .withLabel(SPARK_APP_ID_LABEL, TEST_SPARK_APP_ID))
+      .thenReturn(podOperations)
+    when(podOperations
+      withLabel(SPARK_ROLE_LABEL, SPARK_POD_EXECUTOR_ROLE))
+      .thenReturn(podOperations)
+    when(podOperations
+      .withLabel(SPARK_EXECUTOR_ID_LABEL, "1"))
+      .thenReturn(labeledPods)
     snapshotsStore.notifySubscribers()
     verify(labeledPods).delete()
     verify(podOperations).create(podWithAttachedContainerForId(2))