Revert "grub-core/genmoddep.awk: Ensure output is deterministic"

This reverts commit 87648e9c12a32bddb005b899edc44c2c9c63df82.

We don't ship gawk, so we can't use asorti.  The old way worked fine enough.

--- grub-2.12-rc1/grub-core/genmoddep.awk.old	2023-07-10 15:43:48.000000000 +0000
+++ grub-2.12-rc1/grub-core/genmoddep.awk	2023-10-01 07:52:03.407286373 +0000
@@ -59,9 +59,7 @@
     }
     modlist = ""
     depcount[mod] = 0
-    n = asorti(uniqmods, w)
-    for (i = 1; i <= n; i++) {
-      depmod = w[i]
+    for (depmod in uniqmods) {
       modlist = modlist " " depmod;
       inverse_dependencies[depmod] = inverse_dependencies[depmod] " " mod
       depcount[mod]++