patch 8.2.2162: Vim9: Cannot load or store autoload variables

Problem:    Vim9: Cannot load or store autoload variables.
Solution:   Add ISN_LOADAUTO and ISN_STOREAUTO. (closes #7485)
diff --git a/src/dict.c b/src/dict.c
index 051ba2f..5abb996 100644
--- a/src/dict.c
+++ b/src/dict.c
@@ -1073,7 +1073,7 @@
 			&& HI2DI(hi2)->di_tv.v_type == VAR_FUNC
 			&& var_wrong_func_name(hi2->hi_key, di1 == NULL))
 		    break;
-		if (!valid_varname(hi2->hi_key))
+		if (!valid_varname(hi2->hi_key, TRUE))
 		    break;
 	    }
 	    if (di1 == NULL)