patch 8.2.0419: various memory leaks in Vim9 script code

Problem:    Various memory leaks in Vim9 script code.
Solution:   Fix the leaks. (Ozaki Kiichi, closes #5814)
diff --git a/src/vim9script.c b/src/vim9script.c
index ce5cfec..e74a7b9 100644
--- a/src/vim9script.c
+++ b/src/vim9script.c
@@ -119,11 +119,13 @@
 
     for (idx = 0; idx < si->sn_imports.ga_len; ++idx)
     {
-	imported_T *imp = ((imported_T *)si->sn_imports.ga_data + idx);
+	imported_T *imp = ((imported_T *)si->sn_imports.ga_data) + idx;
 
 	vim_free(imp->imp_name);
     }
     ga_clear(&si->sn_imports);
+    ga_clear(&si->sn_var_vals);
+    ga_clear(&si->sn_type_list);
 }
 
 /*