TYPO3 Core

This bug is resut of #25805, but now core scheduler tasks are affected, so it becomes more critical.

In a nutshell:
1. You must have 2 or more FAL storages.
2. Create a scheduler's task "Update storage index".
3. Select any storage, except the first one, which appears in "Storage to index" drop-down.
4. Save.
5. No matter, what have you selected, you will always get the first storage form a drop-down.

You must edit tasks and select stoarge again.

The reason is in fact, that there is hidden set of fields for "Extract metadata in storage" system task, which also has a "tx_scheduler[scheduler_fileStorageIndexing_storage]" field and on task creation it overwrites selection.