patch 8.2.0536: Vim9: some compilation code not tested

Problem:    Vim9: some compilation code not tested.
Solution:   Add more test cases.
diff --git a/src/proto/evalvars.pro b/src/proto/evalvars.pro
index 4338b20..352097d 100644
--- a/src/proto/evalvars.pro
+++ b/src/proto/evalvars.pro
@@ -28,7 +28,7 @@
 dict_T *get_globvar_dict(void);
 hashtab_T *get_globvar_ht(void);
 dict_T *get_vimvar_dict(void);
-int find_vim_var(char_u *name);
+int find_vim_var(char_u *name, int *di_flags);
 void set_vim_var_type(int idx, vartype_T type);
 void set_vim_var_nr(int idx, varnumber_T val);
 char *get_vim_var_name(int idx);