Copy Again runtime_params into Restart Exec Command

Potentially needs a backport from @EZoni in https://github.com/ECP-WarpX/regression_testing/pull/14:

> I think this is a bug: when we restart a test, we need to copy again into the execution command the runtime parameters passed as `runtime_params` in the `.ini` file, otherwise some input parameters might differ between the original run and the one that is restarted from a checkpoint.