Drop unused jump_counter

compiler/mono/src/decision_tree.rs

@@ -910,9 +910,6 @@ pub fn optimize_when<'a>(
         &jumps,
     );
 
-    // increase the jump counter by the number of jumps in this branching structure
-    *env.jump_counter += jumps.len() as u64;
-
     Expr::Store(stores, env.arena.alloc(expr))
 }
 

compiler/mono/src/expr.rs

@@ -252,7 +252,6 @@ pub struct Env<'a, 'i> {
     pub problems: &'i mut std::vec::Vec<MonoProblem>,
     pub home: ModuleId,
     pub ident_ids: &'i mut IdentIds,
-    pub jump_counter: &'a mut u64,
 }
 
 impl<'a, 'i> Env<'a, 'i> {