If Trump signs this, he deserves any impeachment hearing that comes his way in 2019 for he will have shown he’s not smart enough to govern.
Trump is on the horns of a dilemma. He has to have the military buildup funding right away, which is why he will sign this bill. Trump is preparing for the inevitable eventuality that he will need to initiate a preemptive strike against North Korea in the very imminent future. (Hence his hiring of John Bolton as his National Security Advisor, his being a N. Korea policy hawk.) Trump must have that military funding in place, and thus he will not veto this bill.
It’s all about priorities, and North Korea, with its immediate dangers, trumps (pardon the pun) all. Trump is practical and realistic and knows what his priorities must be. So be it.