### Summary

Adds the first pass at `#[gpui::bench]`, backed by Criterion, with a new
`BenchAppContext` for GPUI benchmarks.

This ports one editor benchmark to the new setup while keeping the
existing Criterion render benchmarks in place.

### Follow Ups

I eventually want to improve this framework to create custom tracy
profiles that includes additional information such as
- notify count
- entity.update count and time
- event emitted and time for that

I also want to use this to create custom measurements so benches can be
used for
- Frames dropped 
- foreground thread time
- Render time
- etc


This PR is a very small proof of initial concept and I'll continue to
build this infrastructure out so Zed and other gpui apps can become a
lot more resilient to dropping frames and hangs. Plus it will make
improving performance a lot easier as well in the future.


Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A