TYPO3 Core

Problem:
If you have non-admin BE users that have access to multiple file mounts through the filelist module, they get duplicate entries in the foldertree when using collapse/expand in the foldertree.

There are actual two problems, that might be related. The result is that some editors get a bug when using the foldertree and have multiple filemounts. (see screenshot)

Solution:
1. Change the div - wraps like in #20722 - only for filelistfoldertree.
2. if running in AJAX mode, don't loop through all filemounts but break on the one that is used

Additional Info:
#20722 introduced the additional wraps
#20722 fixed it only for webpagetree

How to reproduce:

1) Add a couple of file mounts, each should have a nice hierarchical directory structure (at least two levels).
2) Add a BE user (non-admin) that is allowed to see the filelist and these file mounts.
3) Switch to that user, and navigate through the first file mount in the foldertree. Once you collapse and expand the subfolders again, you'll notice that the other file mounts get added again.
4) Apply the patch and try again
5) The problem is gone.
(issue imported from #M14315)