waitid02: cleanup

Remove useless comments, convert spaces to tabs
and fix long lines.

Signed-off-by: Jan Stancek <jstancek@redhat.com>
waitid02: split code into separate testcases

Previous code in main was:
- using sleep for synchronization
  The sleep make take longer if run in overcommitted
  z/VM environment with considerably high steal time, which
  causes testcase to hang.
- missing wait for last child

This patch splits code from main() into separate testcases,
each with its own setup/cleanup and expected outcome.

Signed-off-by: Jan Stancek <jstancek@redhat.com>
Acked-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-By: Cyril Hrubis <chrubis@suse.cz>