Which kinds of invalid nodes does Bulk API accept?

[enikao]

Candidates:

Candidate	can be stored?	Can be retrieved?
serializationVersion missing/invalid	❌	❌
UsedLanguage missing/invalid	❌	❌
UsedLanguage is missing the for any metapointer in same request	❌	❌
UsedLanguage not used in any metapointer in same request	✔️	✔️
Node.id missing/invalid	❌	❌
Node.parent missing/invalid	❌	❌
Node.parent null	❌	❌
Node.parent node with that id not part of same request	✔️	✔️
Node.parent node with that id unknown to repo	❌	❌
Node.annotations node with that id not part of same request	✔️	✔️
Node.annotations node with that id unknown to repo	❌	❌
Node.annotations node with that not an annotation	✔️	✔️
Node.classifier metapointer unknown	✔️	✔️
Node.containments metapointer unknown	✔️	✔️
Node.containments metapointer not part of node's classifier	✔️	✔️
Node.containments node with that id not part of same request	✔️	✔️
Node.containments node with that id unknown to repo	❌	❌
Node.containments node with that id doesn't adhere to containment metapointer type	✔️	✔️
Node.containments node with that not is annotation	✔️	✔️
Node.properties metapointer unknown	✔️	✔️
Node.properties metapointer not part of node's classifier	✔️	✔️
Node.properties value neither null nor string	❌	❌
Node.properties value doesn't adhere to metapointer type	✔️	✔️
Node.references metapointer unknown	✔️	✔️
Node.references metapointer not part of node's classifier	✔️	✔️
Node.references node id null	✔️	✔️
Node.references node resolveInfo null	✔️	✔️
Node.references node with that id not part of same request	✔️	✔️
Node.references node with that id unknown to repo	✔️	✔️
Node.references node with that id doesn't adhere to reference metapointer type	✔️	✔️

[enikao]

Relates to #228