starpu: Factorize the worker id setting through the request

runtime/starpu/codelets/codelet_dlag2z.c

runtime/starpu/codelets/codelet_dzasum.c

runtime/starpu/codelets/codelet_map.c

runtime/starpu/codelets/codelet_zaxpy.c

runtime/starpu/codelets/codelet_zbuild.c

runtime/starpu/codelets/codelet_zcesca.c

runtime/starpu/codelets/codelet_zgeadd.c

runtime/starpu/codelets/codelet_zgelqt.c

runtime/starpu/codelets/codelet_zgemm.c

runtime/starpu/codelets/codelet_zgemv.c

runtime/starpu/codelets/codelet_zgeqrt.c

runtime/starpu/codelets/codelet_zgessm.c

runtime/starpu/codelets/codelet_zgessq.c

runtime/starpu/codelets/codelet_zgesum.c

runtime/starpu/codelets/codelet_zgetrf.c

runtime/starpu/codelets/codelet_zgetrf_incpiv.c

runtime/starpu/codelets/codelet_zgetrf_nopiv.c

runtime/starpu/codelets/codelet_zgram.c

runtime/starpu/codelets/codelet_zhe2ge.c

runtime/starpu/codelets/codelet_zhemm.c