Remove quick_symbol_functions::relocated

quick_symbol_functions::relocated is only needed for psymtabs, and
there it is only needed for Rust.  However, because we've switched the
DWARF reader away from psymtabs, this means there's no longer a need
for this method at all.

gdb/objfiles.c

@@ -667,10 +667,6 @@ objfile_relocate1 (struct objfile *objfile,
       }
   }
 
-  /* Notify the quick symbol object.  */
-  for (const auto &iter : objfile->qf)
-    iter->relocated ();
-
   /* Relocate isolated symbols.  */
   {
     struct symbol *iter;