[EASY] Parallelize post processing in run loop (#3013)

# Description
When we briefly stored all fee policies for a given auction in the post
processing it increased the time for that critical section quite
significantly.
That change was removed since then but the learning still stands that
these operations might as well happen in parallel.

# Changes
Run the 3 DB inserts futures of the run loop post processing in
parallel.

## How to test
It's a very small change so the e2e tests should be sufficient

crates/autopilot/src/run_loop.rs

@@ -18,11 +18,11 @@ use {
         solvable_orders::SolvableOrdersCache,
     },
     ::observe::metrics,
-    anyhow::{Context, Result},
+    anyhow::Result,
     database::order_events::OrderEventLabel,
     ethcontract::U256,
     ethrpc::block_stream::BlockInfo,
-    futures::future::BoxFuture,
+    futures::{future::BoxFuture, TryFutureExt},
     itertools::Itertools,
     model::solver_competition::{
         CompetitionAuction,
@@ -458,28 +458,21 @@ impl RunLoop {
         };
 
         tracing::trace!(?competition, "saving competition");
-        self.persistence
-            .save_competition(&competition)
-            .await
-            .context("failed to save competition")?;
-
-        self.persistence
-            .save_surplus_capturing_jit_orders_orders(
-                auction_id,
-                &auction.surplus_capturing_jit_order_owners,
-            )
-            .await
-            .context("failed to save surplus capturing jit order owners")?;
+        futures::try_join!(
+            self.persistence
+                .save_competition(&competition)
+                .map_err(|e| e.0.context("failed to save competition")),
+            self.persistence
+                .save_surplus_capturing_jit_orders_orders(
+                    auction_id,
+                    &auction.surplus_capturing_jit_order_owners,
+                )
+                .map_err(|e| e.0.context("failed to save jit order owners")),
+            self.persistence
+                .store_fee_policies(auction_id, fee_policies)
+                .map_err(|e| e.context("failed to fee_policies")),
+        )?;
 
-        tracing::info!("saving fee policies");
-        if let Err(err) = self
-            .persistence
-            .store_fee_policies(auction_id, fee_policies)
-            .await
-        {
-            Metrics::fee_policies_store_error();
-            tracing::warn!(?err, "failed to save fee policies");
-        }
         Metrics::post_processed(start.elapsed());
         Ok(())
     }
@@ -1013,13 +1006,6 @@ impl Metrics {
             .inc_by(unsettled.len() as u64);
     }
 
-    fn fee_policies_store_error() {
-        Self::get()
-            .db_metric_error
-            .with_label_values(&["fee_policies_store"])
-            .inc();
-    }
-
     fn post_processed(elapsed: Duration) {
         Self::get()
             .auction_postprocessing_time