PHOENIX-1344 fix duplicit values in NTH_VALUE function

I've fixed issue PHOENIX-1344, but there is one thing: the NTH_VALUE function is not deterministic now.  Nondeterministic come to light when nth value could be any of values as long as "ordered by" values are duplicit. Methond getDeterminism is implemented in parent: AggregateFunction and returns Determinism.PER_ROW. Is that ok?
I've used LinkedList (over ArrayDeque) for storing multiple values to one "ordered by" key cos LinkedList can hold null values and there can be in future switch for respect null values.