Move validation specific customisations out of reconstruction custom, so that reconstruction can run without validation
Merge pull request #4939 from mark-grimes/fixShashlikSequenceWithoutValidation

Fix Shashlik reco customisation when validation not present
Create copy of ShashlikTopology because the object gets deleted at the end of the method
Re-enable Multi5x5ClusterProducer for Shashlik now that it no longer crashes