Add CoverageSpec to PactTests

[emilypi]

This PR adds CoverageSpec to the Pact test suite. It was not enabled during #1151, but passes locally, and via cabal run tests.

PR checklist:

• (N/A) Test coverage for the proposed changes
• PR description contains example output from repl interaction or a snippet from unit test output
• (N/A) Documentation has been updated if new natives or FV properties have been added. To generate new documentation, issue cabal run tests. If they pass locally, docs are generated.
• (N/A) Any changes that could be relevant to users have been recorded in the changelog
• (N/A) In case of changes to the Pact trace output (pact -t), make sure pact-lsp is in sync.

Additionally, please justify why you should or should not do the following:

• (N/A) Confirm replay/back compat
• (N/A) Benchmark regressions
• (N/A) (For Kadena engineers) Run integration-tests against a Chainweb built with this version of Pact