That's a big stretch of a headline based on what they're quoting. Trump was certainly being his inflammatory asshole self, and seemed to opine on what he thought the Lt Gov should or shouldn't do. I didn't read his words in an intimidating way at all though.
It came off more as a brash "he shouldn't testify because he doesn't know what he's talking about" as opposed to "he shouldn't or else bad things might happen".