test(ecstore): deflake multipart listing tests under plain cargo test (#5730)

Multipart upload ids embed the process-global deployment id at both create time and list time. Under plain cargo test (thread-parallel, shared process globals) a concurrently running test that re-initializes a store can swap the global between the two reads, making full-upload-id equality assertions fail spuriously (observed: core::sets::tests::list_multipart_uploads_merges_all_sets_without_pagination_loss failing when run concurrently with bucket::quota tests, passing in isolation).

Add a test-only upload_uuid_suffix helper next to deployment_upload_id and make the affected assertions compare only the decoded <uuid>x<timestamp> suffix. Where suffix normalization changes within-key ordering (base64 alphabet order is not byte order), both sides are sorted before comparison. nextest/CI is unaffected (process-per-test); this only hardens local plain cargo test runs.

crates/ecstore/src/core/sets.rs

@@ -1749,7 +1749,19 @@ mod tests {
             upload_id_marker = page.next_upload_id_marker;
         }
 
-        assert_eq!(actual, expected, "set-level merge must return every upload exactly once");
+        // Compare only the decoded `<uuid>x<timestamp>` suffixes: the full
+        // upload id embeds the process-global deployment id, which a
+        // concurrently running test can swap between create and list time.
+        let normalize = |uploads: &[(String, String)]| {
+            let mut normalized = uploads
+                .iter()
+                .map(|(key, upload_id)| (key.clone(), runtime_sources::upload_uuid_suffix(upload_id)))
+                .collect::<Vec<_>>();
+            normalized.sort();
+            normalized
+        };
+        let actual = normalize(&actual);
+        assert_eq!(actual, normalize(&expected), "set-level merge must return every upload exactly once");
         let mut deduped = actual.clone();
         deduped.dedup();
         assert_eq!(deduped.len(), actual.len(), "set-level pagination must not duplicate uploads");