Bump tests/third_party/yosys from 81df855 to 59404f8

Bumps [tests/third_party/yosys](https://github.com/YosysHQ/yosys) from `81df855` to `59404f8`.
- [Release notes](https://github.com/YosysHQ/yosys/releases)
- [Commits](YosysHQ/yosys@81df855...59404f8)

---
updated-dependencies:
- dependency-name: tests/third_party/yosys
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>