Assigning idcpu in one go

[ax3l]

I think it would be efficient if we had a function that is make64bit(cpu, id) that we can assign straight to the idcpu array value:

pa_idcpu[ip] = newFunction(cpuid, pid+ip);

Do we have such a thing already?

I work around this now via

pa_idcpu[ip] = 0;
amrex::ParticleIDWrapper{pa_idcpu[ip]} = pid+ip;
amrex::ParticleCPUWrapper{pa_idcpu[ip]} = cpuid;

to avoid valgrind (uninit data read) warnings during the first assign.

x-ref: ECP-WarpX/WarpX#4653