fixing release build

Signed-off-by: Jakub Doka <jakub.doka2@gmail.com>

cranelift-backend/src/lib.rs

@@ -91,7 +91,6 @@ impl hblang::backend::Backend for Backend {
 
         self.globals.shadow(types.ins.globals.len());
 
-        #[cfg(debug_assertions)]
         let mut seen_names = HashSet::new();
 
         self.asm.frontier.push(from.into());