6951188: CMS: move PromotionInfo into its own file Summary: Moved PromotionInfo and friends into new files promotionInfo.{h,c}pp from their previous compactibleFreeListSpace.{h,c}pp home. Reviewed-by: apetrusenko

^build/
^dist/
^drop/
^drop_included/
^webrev/
/nbproject/private/