Don't read the newline character to line buffer because lines are passed

Don't read the newline character to line buffer because lines are passed
to wcscoll(3). Newline characters could cause incorrect results when
comparing lines.

Also, if an input line didn't contain a newline character, it was
omitted from the output. According to my interpretation, SUSv3 requires
that the newline is always printed.

Add regression tests for the cases. [1]

PR:		bin/140976
Submitted by:	D'Arcy Cain (original version) [1]
Approved by:	trasz (mentor)