Add --modify-fds=[no|high] option

Add --modify-fds=[no|high] option

Normally a newly recreated file descriptor gets the lowest number
available. This might cause old file descriptor numbers to be reused
and hides bad file descriptor accesses (because the old number is
new again).

When enabled, when the program opens a new file descriptor,
the highest available file descriptor is returned instead of the
lowest one.

Add the none/tests/track_new.stderr.exp test to test this
new option.
use_after_close
Adjust none/tests/filter_fdleak to filter the track_new.vgtest,
because of the fdleak changes, the output of the use_after_close
test also had to be adjusted. ALso adjust the none/tests/cmdline1
and none/tests/cmdline2 output as the new --modify-fds=no|high is
displayed.

https://bugs.kde.org/show_bug.cgi?id=493433