fix tar-year.sh, removed use of .tar.tstamp files

Eliminated the need for the `.tar.tstamp` files.  It became intractable
to produce a tarball that was byte-for-byte identical to a tarball
on another platform.  We further simplified the process used by the
`bin/tar-year.sh` tool to no longer need `.tar.tstamp` files.
Removed `.tar.tstamp` files and updated the manifest.
Sorry (tm Canada 🇨🇦) for the "flip-flop".

The `bin/tar-year.sh` tool now uses a similar algorithm to how
`bin/tar-entry.sh` determines if a compressed tarball needs to be
rebuilt.

Changed `bin/tar-entry.sh` VERSION from "1.3.3 2024-03-27"
to "1.3.4 2024-03-27".

Changed `bin/tar-year.sh` VERSION from "1.1.3 2024-03-27"
to "1.2 2024-03-27".

Performed `make www` and `make form_entry_tarball`
and `make form_year_tarball` to complete the above
actions and test these changes under macOS.

TODO: Test the `bin/tar-year.sh` tool under Linux.

TODO: Address issues with building the top level `ioccc.tar.bz2`
      and the `bin/tar-all.sh` tool and the `make form_all_tarball` rule.

NOTE: The `bin/tar-all.sh` tool and the `make form_all_tarball` rule
and the `make tar` should **NOT** be used at this time.

1984/.filelist

@@ -4,5 +4,4 @@
 1984/Makefile
 1984/README.md
 1984/rules.txt
-1984/.tar.tstamp
 1984/.year