[SPARK-16375][WEB UI] Fixed misassigned var: numCompletedTasks was assigned to numSkippedTasks

## What changes were proposed in this pull request?

I fixed a misassigned var,  numCompletedTasks was assigned to numSkippedTasks in the convertJobData method

## How was this patch tested?

dev/run-tests

Author: Alex Bozarth <ajbozart@us.ibm.com>

Closes apache#14141 from ajbozarth/spark16375.

Author: ajbozarth

core/src/main/scala/org/apache/spark/status/api/v1/AllJobsResource.scala

@@ -91,7 +91,7 @@ private[v1] object AllJobsResource {
         numTasks = job.numTasks,
         numActiveTasks = job.numActiveTasks,
         numCompletedTasks = job.numCompletedTasks,
-        numSkippedTasks = job.numCompletedTasks,
+        numSkippedTasks = job.numSkippedTasks,
         numFailedTasks = job.numFailedTasks,
         numActiveStages = job.numActiveStages,
         numCompletedStages = job.completedStageIndices.size,

core/src/test/resources/HistoryServerExpectations/job_list_from_multi_attempt_app_json_1__expectation.json

@@ -6,7 +6,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,

core/src/test/resources/HistoryServerExpectations/job_list_from_multi_attempt_app_json_2__expectation.json

@@ -6,7 +6,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,

core/src/test/resources/HistoryServerExpectations/job_list_json_expectation.json

@@ -6,7 +6,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,
@@ -20,7 +20,7 @@
   "numTasks" : 16,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 15,
-  "numSkippedTasks" : 15,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 1,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,
@@ -34,7 +34,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,

core/src/test/resources/HistoryServerExpectations/one_job_json_expectation.json

@@ -6,7 +6,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,

core/src/test/resources/HistoryServerExpectations/succeeded_failed_job_list_json_expectation.json

@@ -6,7 +6,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,
@@ -20,7 +20,7 @@
   "numTasks" : 16,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 15,
-  "numSkippedTasks" : 15,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 1,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,
@@ -34,7 +34,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,

core/src/test/resources/HistoryServerExpectations/succeeded_job_list_json_expectation.json

@@ -6,7 +6,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,
@@ -20,7 +20,7 @@
   "numTasks" : 8,
   "numActiveTasks" : 0,
   "numCompletedTasks" : 8,
-  "numSkippedTasks" : 8,
+  "numSkippedTasks" : 0,
   "numFailedTasks" : 0,
   "numActiveStages" : 0,
   "numCompletedStages" : 1,