fails:Enumerator::Lazy#drop_while returns a new instance of Enumerator::Lazy
fails:Enumerator::Lazy#drop_while sets nil to size
fails:Enumerator::Lazy#drop_while calls the block with initial values when yield with multiple arguments
fails:Enumerator::Lazy#drop_while raises an ArgumentError when not given a block
fails:Enumerator::Lazy#drop_while when the returned lazy enumerator is evaluated by Enumerable#first stops after specified times
fails:Enumerator::Lazy#drop_while on a nested Lazy sets nil to size
fails:Enumerator::Lazy#drop_while on a nested Lazy when the returned lazy enumerator is evaluated by Enumerable#first stops after specified times
