* Fix path_open granting more rights than requested
* Add missing rights checks in: fd_fdstat_set_flags, fd_filestat_get, poll_oneoff
* Fix `open_scratch_directory` not requesting any rights.
* Properly request needed rights in various tests
* Add some extra trace-level logging
* Remove a no-op restriction of rights to the ones returned by
`determine_type_rights`. It was redundant, because `FdEntry:from`
internally also called `determine_type_rights` and only dropped some of them.