Suspend Windows processes until job objects are set up

[HertzDevil]

Under rare conditions, a newly created Windows process might have terminated so fast that LibC.AssignProcessToJobObject fails with ERROR_ACCESS_DENIED, because it requires an alive process (e.g. https://github.com/crystal-lang/crystal/actions/runs/15293884475/job/43022118390). This PR prevents that by creating the process in a suspended state and resuming it after the LibC.AssignProcessToJobObject call.

In this case, LibC.GetExitCodeProcess inside #wait must return a valid exit code that isn't LibC::STILL_ACTIVE.