Merge pull request containerd#10764 from saketjajoo/saketjajoo/3787-race-condition-1.6

[release/1.6] Fix the race condition during GC of snapshots when client retries

Author: samuelkarp

unpacker.go

@@ -142,13 +142,6 @@ func (u *unpacker) unpack(
 		}
 		defer unlock()
 
-		if _, err := sn.Stat(ctx, chainID); err == nil {
-			// no need to handle
-			return nil
-		} else if !errdefs.IsNotFound(err) {
-			return fmt.Errorf("failed to stat snapshot %s: %w", chainID, err)
-		}
-
 		// inherits annotations which are provided as snapshot labels.
 		labels := snapshots.FilterInheritedLabels(desc.Annotations)
 		if labels == nil {