Bump third-party/verilator/master from 21dbdbf to 5a5c38e (#865)

Bumps [third-party/verilator/master](https://github.com/verilator/verilator) from `21dbdbf` to `5a5c38e`.
- [Commits](verilator/verilator@21dbdbf...5a5c38e)

---
updated-dependencies:
- dependency-name: third-party/verilator/master
  dependency-version: 5a5c38e47865733ca5d12ab0fec55218fbb4c8ea
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]