exa2pro/starpu-max: porting work to Maxeler DFE @ 888effa7e35b8b655d30cbc33cd9ebea4c11d9ef

Cédric Augonnet 47af90d6fe Bug fix. When an "empty task" (cl = NULL) is executable, it is directly		16 lat temu
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cpu	47af90d6fe Bug fix. When an "empty task" (cl = NULL) is executable, it is directly	16 lat temu
cuda	47af90d6fe Bug fix. When an "empty task" (cl = NULL) is executable, it is directly	16 lat temu
gordon	47af90d6fe Bug fix. When an "empty task" (cl = NULL) is executable, it is directly	16 lat temu
opencl	47af90d6fe Bug fix. When an "empty task" (cl = NULL) is executable, it is directly	16 lat temu