message: Remove test assertion sensitive to background segment merging
diff: @@ -283,7 +283,6 @@ mod tests {
  let warming_state = &reader.inner.warming_state;
  let searcher = reader.searcher();
  - assert_eq!(searcher.segment_readers().len(), num_writer_threads);
  assert!(
  !warming_state.gc_maybe(),
  "no GC after first searcher generation"
  