Last I've heard no JS engine ships or wants to ship PTC. So I'd be surprised if V8 breaks away from the pack there, given that nothing changed.
https://github.com/tc39/ecma262/issues/535
https://github.com/rwaldron/tc39-notes/blob/master/es7/2016-...
For all of Google's talk about their syntactic tail call proposal, they haven't cared enough to implement it -- only to remove their PTC code. FF and MS are in the same position. At this point, I don't really care one way or the other, they need to quit the excuses, quit the petty power struggles, and do something one way or the other. Every year they wait is another year before we can use it.
EDIT: I'd also add that the performance impact in the real world seems to be close to zero.