- fix Min/Max in case 1 processor get only empty tiles - start to remove unnecessary counter-mate computation    (but might be able to remove much more)
- fix Min/Max in case 1 processor get only empty tiles
- start to remove unnecessary counter-mate computation
   (but might be able to remove much more)

altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h