Add testLawsGroup QuickCheck utility function

[koslambrou]

Description

This should be used instead of Test.QuickCheck.Classes.lawsCheckOne, which reports through Test.QuickCheck.quickCheck. That writes straight to stdout, thus it is not properly indented in the test console output. It also discards the QuickCheck Result, which means that a violated law does not fail the test suite.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• All visible changes are prepended to the latest section of a CHANGELOG.md for the affected packages.
  New section is never added with the code changes. (See RELEASING.md)
• When applicable, versions are updated in .cabal and CHANGELOG.md files according to the
  versioning process.
• The version bounds in .cabal files for all affected packages are updated.
  If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• Self-reviewed the diff