Clean `Standard.Test` API up

[JaroslavTulach]

Why?

• Standard.Test is an important API especially ...
• should Make tests part of Enso projects #9039 be implemented ...
• then it would be closely tight to the Enso engine runtime

What?

• currently the API is exposing a lot of implementation details
• some modules can hopefully be hidden - current list available
• some constructors and method can be made private: https://github.com/enso-org/enso/blob/e002d942a5d49ec2d275fdeb8f0c3e62ebaa2906/distribution/lib/Standard/Test/0.0.0-dev/docs/api/Bench.md

[JaroslavTulach]

• At least following actions are planned:

  • Move Faker to test/Benchmarks - not used anywhere else
  • Copy run_with_and_without_output where needed, it doesn't need to be in an API
  • Move Should_Reach to Error_Spec - the only place where it is used - done in 3d6d26e
  • there is Test_Result and Spec_Result - unify!
  • Eliminate Test_Environment!?
  • Hide Suite.name_matches
  • Why there is Standard.Test.Problems?

• Some elements will be made private in Make Standard.Test pending field lazy #14536