Bump chiseltest from `cb9b2c4` to `9f408a5` (#314)

Bumps [chiseltest](https://github.com/ucb-bar/chisel-testers2) from `cb9b2c4` to `9f408a5`.
- [Release notes](https://github.com/ucb-bar/chisel-testers2/releases)
- [Commits](https://github.com/ucb-bar/chisel-testers2/compare/cb9b2c48bc5646285f33f66ba2a2826700cf54db...9f408a51e987e2a6523fbbc0eb9a0981b0245cf7

)

---
updated-dependencies:
- dependency-name: chiseltest
  dependency-type: direct:production
...

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