Context: truncate files vector
Created by: jaje
Problem: Size of context files vector is never reduced.
Solution: Adjust files vector to smallest size if possible.
Changes introduced by this pull request:
- Truncate files vector length if possible.
- Shrink files vector capacity if possible.
Drawbacks: If process opens and closes lots of files, this change may increase count of relocation.
Fixes: no related issue
State: ready