When you’ve only lived for a decade, the next one stretches ahead of you like an apparent eternity. To the elders raising you, it goes by in the blink of an eye. Docmakers Itab Azzam and Jack MacInnes maintain both those perspectives in their film “ One in a Million ,” charting changes at once vast and disorientingly swift in the life of a young Syrian refugee estranged from her past and unsure of her future — and in the present, growing up faster than her similarly unmoored parents can process.