Keep last file positions in last-use ordering

Keep last file positions in last-use ordering

Using a map would sort the elements in alphabetic ordering, which
means that when the number of elements is larger than 100, the wrong
elements get pruned.

This commit uses a list instead. Searching an item needs linear time,
but this should not be a problem for a list with less than 100
elements.

Fixes bug #10310.

(cherry picked from commit 58d22e0c6edab4cb68af63d3ccaafcb875be995d)