logd: fix kernel logline stutter

(cherry pick from commit 2c3b300f)

- look for cases where one log line contains two without a newline.
- rare condition, occurs when a printk does not have
  a terminating newline under certain race conditions.
- the newline may be performed broken up as a second call
- the timestamps can be reversed (showing the race effects).
- driver(s) should really have the newline in their log messages.

Change-Id: Ibfb56b32047da3d6513db059ca6edad0f0105168