minor, stabilise the wheap sort

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
test, provide regression for stable sorting upon print

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
test, adapt older printing regressions to new stabilised sort

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'cmd/print--unique'

* cmd/print--unique:
  test, adapt older printing regressions to new stabilised sort
  test, provide regression for stable sorting upon print
  minor, stabilise the wheap sort