Revert "Issue #29094: Offsets in a ZIP file created with extern file object and modes" (#1467)

This reverts commit 0f4ed2cdc6e7887153c481f4c7298bc35e219d84 (though, the tests are retained) and the followup 58ab4b57da2e5db7ff9b9940dd21bbbe4d804957.

See discussion on bpo-29094.
2 files changed