Adding failing test case for #6089 - serialization causes notices
Hotfix for #6089 - `protectedProperties` of ArrayObject are maintained on serialization
Merge pull request #6092 from Ocramius/hotfix/#6089-arrayobject-serialization

Hotfix for #6089 - ArrayObject serialization doesn't restore `protectedProperties`
Merge branch 'hotfix/6092'

Close #6092
Fixes #6089