Trump needs to strike a deal with Cruz to drop out and support Trump. They don't have to like each other to strike a political deal. Happens all the time. In return for Cruz stepping aside, Trump dangles the Supreme Court nomination carrot in front of Cruz.
Cruz is a much better fit as a Supreme Court justice than he would be as president. Trump, with his executive decision-making skills, is better suited as the chief executive. Cruz would fly through Senate confirmation because the senators don't like Cruz and would love to get rid of him. Here's a way how to accomplish that.
With Cruz's delegates now promised to Trump, Trump wins the nomination before the convention and blows Hillary out of the water in November. I do not believe any of the polls saying that Trump will lose to Hillary in the general election. No way you put those two on the stump together, that Donald doesn't beat Hillary going away. He's got high dislikable ratings? Well, so does Hillary. Remember, she's got an email-server-national-security-violations albatross hanging from around her neck,. So Trump having a ton of negative baggage himself, just levels the playing field some.
This scenario is a win, win, win situation to break the stalemate between the Trump and Cruz camps.
It’s too early to put Cruz in the SCOTUS. It’s nice to say he’d be a better justice than a president, but then give me the list of who you want to be president after Trump. I doubt you’d find anyone better than Cruz.
The deal would have to be Cruz as V.P. and Cruz gets to pick all the SCOTUS appointments at a minimum.