* init.cfg (require_inotify_supported_): A new function that
indicates inotify support for a file in the current directory,
using tail --debug, rather than awkward strace checks etc.
* tests/tail/inotify-dir-recreate.sh: Call require_inotify_supported_.
tests/tail/inotify-only-regular.sh: Likewise.
tests/tail/inotify-race.sh: Likewise.
tests/tail/inotify-race2.sh: Likewise.