update tests to match recent post-return change

Signed-off-by: Joel Dice <[email protected]>

Author: dicej

crates/misc/component-async-tests/tests/scenario/round_trip.rs

@@ -442,6 +442,7 @@ pub async fn test_round_trip(
                     unreachable!()
                 };
                 assert_eq!(*expected, actual);
+                foo_function.post_return_async(&mut store).await?;
             }
         }
     }

crates/misc/component-async-tests/tests/scenario/round_trip_many.rs

@@ -415,6 +415,7 @@ async fn test_round_trip_many(
                     unreachable!()
                 };
                 assert_eq!(&make(expected), actual);
+                foo_function.post_return_async(&mut store).await?;
             }
         }
     }