patch 8.2.2572: Vim9: crash when getting the types for a legacy function

Problem:    Vim9: crash when getting the types for a legacy function.
Solution:   Initialize the type list growarray. (closes #7929)
diff --git a/src/vim9compile.c b/src/vim9compile.c
index f7bdf31..f6d1fb3 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -274,7 +274,7 @@
  * Lookup a script-local variable in the current script, possibly defined in a
  * block that contains the function "cctx->ctx_ufunc".
  * "cctx" is NULL at the script level.
- * if "len" is <= 0 "name" must be NUL terminated.
+ * If "len" is <= 0 "name" must be NUL terminated.
  * Return NULL when not found.
  */
     static sallvar_T *
@@ -8730,6 +8730,8 @@
     // The type is included in "tt_args".
     if (argcount > 0 || varargs)
     {
+	if (ufunc->uf_type_list.ga_itemsize == 0)
+	    ga_init2(&ufunc->uf_type_list, sizeof(type_T *), 10);
 	ufunc->uf_func_type = alloc_func_type(ufunc->uf_ret_type,
 					   argcount, &ufunc->uf_type_list);
 	// Add argument types to the function type.