add 2nd call to EXCH2_RX1_CUBE: fix Pb when 1 tile-edge connects  to several tiles (e.g. 12 tiles regular Cube); this is a temporary fix  until EXCH_IGNORE_CORNERS is implemented in EXCH2_RX1_CUBE.
add 2nd call to EXCH2_RX1_CUBE: fix Pb when 1 tile-edge connects
 to several tiles (e.g. 12 tiles regular Cube); this is a temporary fix
 until EXCH_IGNORE_CORNERS is implemented in EXCH2_RX1_CUBE.

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