[SPARK-17038][STREAMING] fix metrics retrieval source of 'lastReceivedBatch'

https://issues.apache.org/jira/browse/SPARK-17038

## What changes were proposed in this pull request?

StreamingSource's lastReceivedBatch_submissionTime, lastReceivedBatch_processingTimeStart, and lastReceivedBatch_processingTimeEnd all use data from lastCompletedBatch instead of lastReceivedBatch.

In particular, this makes it impossible to match lastReceivedBatch_records with a batchID/submission time.

This is apparent when looking at StreamingSource.scala, lines 89-94.

## How was this patch tested?

Manually running unit tests on local laptop

Author: Xin Ren <iamshrek@126.com>

Closes #14681 from keypointt/SPARK-17038.

streaming/src/main/scala/org/apache/spark/streaming/StreamingSource.scala

@@ -87,11 +87,11 @@ private[streaming] class StreamingSource(ssc: StreamingContext) extends Source {
   // Gauge for last received batch, useful for monitoring the streaming job's running status,
   // displayed data -1 for any abnormal condition.
   registerGaugeWithOption("lastReceivedBatch_submissionTime",
-    _.lastCompletedBatch.map(_.submissionTime), -1L)
+    _.lastReceivedBatch.map(_.submissionTime), -1L)
   registerGaugeWithOption("lastReceivedBatch_processingStartTime",
-    _.lastCompletedBatch.flatMap(_.processingStartTime), -1L)
+    _.lastReceivedBatch.flatMap(_.processingStartTime), -1L)
   registerGaugeWithOption("lastReceivedBatch_processingEndTime",
-    _.lastCompletedBatch.flatMap(_.processingEndTime), -1L)
+    _.lastReceivedBatch.flatMap(_.processingEndTime), -1L)
 
   // Gauge for last received batch records.
   registerGauge("lastReceivedBatch_records", _.lastReceivedBatchRecords.values.sum, 0L)

streaming/src/test/scala/org/apache/spark/streaming/ui/StreamingJobProgressListenerSuite.scala

@@ -68,6 +68,7 @@ class StreamingJobProgressListenerSuite extends TestSuiteBase with Matchers {
     listener.waitingBatches should be (List(BatchUIData(batchInfoSubmitted)))
     listener.runningBatches should be (Nil)
     listener.retainedCompletedBatches should be (Nil)
+    listener.lastReceivedBatch should be (Some(BatchUIData(batchInfoSubmitted)))
     listener.lastCompletedBatch should be (None)
     listener.numUnprocessedBatches should be (1)
     listener.numTotalCompletedBatches should be (0)
@@ -81,6 +82,7 @@ class StreamingJobProgressListenerSuite extends TestSuiteBase with Matchers {
     listener.waitingBatches should be (Nil)
     listener.runningBatches should be (List(BatchUIData(batchInfoStarted)))
     listener.retainedCompletedBatches should be (Nil)
+    listener.lastReceivedBatch should be (Some(BatchUIData(batchInfoStarted)))
     listener.lastCompletedBatch should be (None)
     listener.numUnprocessedBatches should be (1)
     listener.numTotalCompletedBatches should be (0)
@@ -123,6 +125,7 @@ class StreamingJobProgressListenerSuite extends TestSuiteBase with Matchers {
     listener.waitingBatches should be (Nil)
     listener.runningBatches should be (Nil)
     listener.retainedCompletedBatches should be (List(BatchUIData(batchInfoCompleted)))
+    listener.lastReceivedBatch should be (Some(BatchUIData(batchInfoCompleted)))
     listener.lastCompletedBatch should be (Some(BatchUIData(batchInfoCompleted)))
     listener.numUnprocessedBatches should be (0)
     listener.numTotalCompletedBatches should be (1)