You can safely assume that Trump pushing for a tax amnesty does not have small-time shareholders of public companies in mind. I'd look a little closer at his inner circle where the major beneficiaries of such a move reside.
I'm not discussing who is benefiting from this but the odds of it happening. Also if this benefits Apple shareholders, I doubt this is Trump-clan only.
Trump's score for 'getting things done' is not such that I really worry about this. Maybe if he stopped alienating everybody that this would change but I do not believe he is capable of changing himself in such a fundamental way.