[PR 25789] Add acceptance tests for shared storage recursion hell fix

[PVince81]

Add tests for owncloud/core#25789

Steps are here owncloud/core#25557 (comment).

On v9.1.0 they would fail with a 500 Internal Server Error.
On v9.1.1 they would pass, so the curl / get / download would return success.

Note that the curl command can be replaced by a PROPFIND or anything that would trigger a FS setup for the user.

@davitol

[PVince81]

Integration test to be added on master, stable9.1 and stable9 at least.

[PVince81]

Would be good to add a test for this soon

[PVince81]

@davitol any update ?