fix protocol race condition

libnyx sends a ping packet twice during initialization which
can cause a synchronization problem with QEMU-Nyx

fuzz_runner/src/nyx/qemu_process.rs

@@ -203,7 +203,7 @@ impl QemuProcess {
             }
         };
 
-        if run_qemu(&mut control).is_err() {
+        if wait_qemu(&mut control).is_err() {
             return Err(format!("cannot launch QEMU-Nyx..."));
         }