alternative to display_inventory for window-port

Several window ports that support perm_invent were
using a call back to the core display_inventory()
function.

While calling from the window port back to core functions
is arguably not ideal in the first place, it was recently
brought to light that code NetHack-3.7 code changes to
display_inventory() actually caused it to stop repopulating
the perm_invent window as intended under certain circumstances.

For now, provide an alternative function, repopulate_perminvent(),
that hopefullshould still work the way it did previously.

There will likely be some additional changes after this to
further improve things, at some point.

For now though, this
Resolves #1454

win/curses/cursinvt.c

@@ -96,7 +96,7 @@ curs_update_invt(int arg)
         /* ask core to display full inventory in a PICK_NONE menu;
            instead of setting up an ordinary menu, it will indirectly
            call curs_add_invt() for each line (including class headers) */
-        display_inventory(NULL, FALSE);
+        repopulate_perminvent();
         curs_invt_updated(win);
 
     } else {