[BUGFIX] CF FileBackend unlimited lifetime support

Backport of a bugfix that was part of #39430 in 6.0.

Change-Id: I2266ae12284a139a384854e3ff0bacf23f277859
Resolves: #34886
Related: #39430
Releases: 4.7, 4.5
Reviewed-on: https://review.typo3.org/24073
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn