cardano-cli-golden: protect shared file by a semaphore

[smelc]

Changelog

- description: |
    cardano-cli-golden: protect shared file by a semaphore, to avoid spurious failures
# uncomment types applicable to the change:
  type:
  # - feature        # introduces a new feature
  # - breaking       # the API has changed in a breaking way
  # - compatible     # the API has changed but is non-breaking
  # - optimisation   # measurable performance improvements
  # - refactoring    # QoL changes
  # - bugfix         # fixes a defect
  - test           # fixes/modifies tests
  # - maintenance    # not directly related to the code
  # - release        # related to a new release preparation
  # - documentation  # change in code docs, haddocks...

Context

test/cardano-cli-golden/files/golden/shelley/stake-address/reg-certificate-2.json is being used by two tests and I think this has been creating flakiness in the CI, as visible here (failure happened on #1036, see here and also here on #1038):

How to trust this PR

• Tests pass
• Locking looks good

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• Self-reviewed the diff

[carbolymer]

The semaphore won't help here because there's no race condition on writes here: there's only one producer of this file and one consumer. The problem is the order of operations in CI, sometimes it's being read before it's produced. We're deleting golden files prior to executing cardano-cli-golden to detect potential changes.