Storage accepts tombstone targetting tombstone in multi-shard setup #3498
Description
Expected Behavior
https://pkg.go.dev/github.com/nspcc-dev/neofs-node/pkg/local_object_storage/engine#StorageEngine.Put fails if argument is a tombstone associated with the stored tombstone
Current Behavior
no error
Possible Solution
check all shards 1st, then save tombstone
Steps to Reproduce (for bugs)
unit tests added in #3495. Suggest reproduction in DevEnv
Regression
may be, but not likely