pub fn set_fast_vm_mode(&mut self, fast_vm_mode: FastVmMode) {
        if !matches!(fast_vm_mode, FastVmMode::Old) {
            tracing::warn!(
                "Running new VM with mode {fast_vm_mode:?}; this can lead to incorrect node behavior"
            );
        }
        self.fast_vm_mode = fast_vm_mode;
    }
Sets the fast VM mode used by this executor.
core/lib/vm_executor/src/batch/factory.rs