* grub-core/tests/legacy_password_test.c: New test.

* grub-core/commands/legacycfg.c: Remove variable length arrays.

grub-core/Makefile.core.def

@@ -1921,6 +1921,11 @@ module = {
   common = tests/pbkdf2_test.c;
 };
 
+module = {
+  name = legacy_password_test;
+  common = tests/legacy_password_test.c;
+};
+
 module = {
   name = div_test;
   common = tests/div_test.c;