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.