Use ChangePolicy::min_value in lowest fee tests

If we only add a drain when it wouldn't increase waste then it is
impossible to decrease waste by adding a new input -- but the logic of
the bound function has to account for this situation. So by using
min_value_and_waste we never test it!

Author: LLFourn

tests/lowest_fee.rs

@@ -26,7 +26,7 @@ proptest! {
     ) {
         let params = common::StrategyParams { n_candidates, target_value, base_weight, min_fee, feerate, feerate_lt_diff, drain_weight, drain_spend_weight, drain_dust };
         let candidates = common::gen_candidates(params.n_candidates);
-        let change_policy = ChangePolicy::min_value_and_waste(params.drain_weights(), params.drain_dust, params.feerate(), params.long_term_feerate());
+        let change_policy = ChangePolicy::min_value(params.drain_weights(), params.drain_dust);
         let metric = LowestFee { target: params.target(), long_term_feerate: params.long_term_feerate(), change_policy };
         common::can_eventually_find_best_solution(params, candidates, change_policy, metric)?;
     }
@@ -46,7 +46,7 @@ proptest! {
     ) {
         let params = common::StrategyParams { n_candidates, target_value, base_weight, min_fee, feerate, feerate_lt_diff, drain_weight, drain_spend_weight, drain_dust };
         let candidates = common::gen_candidates(params.n_candidates);
-        let change_policy = ChangePolicy::min_value_and_waste(params.drain_weights(), params.drain_dust, params.feerate(), params.long_term_feerate());
+        let change_policy = ChangePolicy::min_value(params.drain_weights(), params.drain_dust);
         let metric = LowestFee { target: params.target(), long_term_feerate: params.long_term_feerate(), change_policy };
         common::ensure_bound_is_not_too_tight(params, candidates, change_policy, metric)?;
     }
@@ -90,11 +90,9 @@ proptest! {
 
         let mut cs = CoinSelector::new(&candidates, params.base_weight);
 
-        let change_policy = ChangePolicy::min_value_and_waste(
+        let change_policy = ChangePolicy::min_value(
             params.drain_weights(),
             params.drain_dust,
-            params.feerate(),
-            params.long_term_feerate(),
         );
 
         let metric = LowestFee {
@@ -128,12 +126,7 @@ fn combined_changeless_metric() {
     let mut cs_a = CoinSelector::new(&candidates, params.base_weight);
     let mut cs_b = CoinSelector::new(&candidates, params.base_weight);
 
-    let change_policy = ChangePolicy::min_value_and_waste(
-        params.drain_weights(),
-        params.drain_dust,
-        params.feerate(),
-        params.long_term_feerate(),
-    );
+    let change_policy = ChangePolicy::min_value(params.drain_weights(), params.drain_dust);
 
     let metric_lowest_fee = LowestFee {
         target: params.target(),