Cold data control may skip the group with the highest threshold

### Description

ColdDataCgCtrService sorts configured thresholds by subtracting two long values and narrowing the result to int. A large threshold delta can overflow the comparator and place the largest threshold after smaller entries. Because only three groups are decelerated per cycle, the group with the highest threshold can be skipped.

### Expected behavior

Sort thresholds with Long.compare so the three largest eligible groups are always processed.

Start at ColdDataCgCtrService and locate the comparator that orders configured thresholds. Confirm the ordering with a large threshold difference, then verify that the three largest eligible groups are selected for deceleration without comparator overflow.

Written by the indexing model from the issue text.