Make sure to remove thread local data only if we have destructor.

src/shims/tls.rs

@@ -181,8 +181,8 @@ fn fetch_tls_dtor(
         {
             match data.entry(thread_id) {
                 Entry::Occupied(entry) => {
-                    let data_scalar = entry.remove();
                     if let Some(dtor) = dtor {
+                        let data_scalar = entry.remove();
                         let ret = Some((*dtor, data_scalar, key));
                         return ret;
                     }