tests: use igt_fail instead of exit(param != 0)

tests: use igt_fail instead of exit(param != 0)

Mostly a sed job with too manual fixups:
- one case of using _exit instead of exit
- and one case which under some conditions use 77, so convert that
  check to an igt_skip.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>