bug#43828: invalid date converting from UTC, near DST

[Martin Fido]

Hi,

I seem to have found a bug in the date utility, converting from UTC to Sydney 
time. It returns invalid date for what should be perfectly valid:

    $ TZ='Australia/Sydney' date -d '2020-10-04T02:00:00Z'
    date: invalid date ‘2020-10-04T02:00:00Z’

    $ TZ='Australia/Sydney' date -d '2020-10-04T02:59:59Z'
    date: invalid date ‘2020-10-04T02:59:59Z’

Note DST in Sydney changed 10 hours earlier:

    $ TZ='Australia/Sydney' date -d '2020-10-03T15:59:59Z'
    Sunday 4 October  01:59:59 AEST 2020

    $ TZ='Australia/Sydney' date -d '2020-10-03T16:00:00Z'
    Sunday 4 October  03:00:00 AEDT 2020

I have version 8.25:

    $ date --version
    date (GNU coreutils) 8.25
    Copyright (C) 2016 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>.
    This is free software: you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.

    Written by David MacKenzie.

Thanks,

Martin.