exa2pro/starpu-max: porting work to Maxeler DFE @ 0c6c658cb1a3f80f7a56f8a70cc626b7f0c29b22

Nathalie Furmento 0c6c658cb1 tests: turn function static when it makes sense to do so		13 lat temu
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explicit_combined_worker.c	0c6c658cb1 tests: turn function static when it makes sense to do so	13 lat temu
parallel_kernels.c	0c6c658cb1 tests: turn function static when it makes sense to do so	13 lat temu
parallel_kernels_spmd.c	0c6c658cb1 tests: turn function static when it makes sense to do so	13 lat temu
spmd_peager.c	0c6c658cb1 tests: turn function static when it makes sense to do so	13 lat temu