test: allow slow shutdown warning (#4953)

Introduced in #4886, did not consider that tests with real_s3 could
sometimes go over the limit. Do not fail tests because of that.

pageserver/src/lib.rs

@@ -226,6 +226,7 @@ async fn timed<Fut: std::future::Future>(
 
             let ret = fut.await;
 
+            // this has a global allowed_errors
             tracing::warn!(
                 task = name,
                 elapsed_ms = started.elapsed().as_millis(),

test_runner/fixtures/neon_fixtures.py

@@ -1518,6 +1518,8 @@ class NeonPageserver(PgProtocol):
             # Pageserver timeline deletion should be polled until it gets 404, so ignore it globally
             ".*Error processing HTTP request: NotFound: Timeline .* was not found",
             ".*took more than expected to complete.*",
+            # these can happen during shutdown, but it should not be a reason to fail a test
+            ".*completed, took longer than expected.*",
         ]
 
     def start(