MsTest: Only use TestContext for output and not Console.WriteLine

[obligaron]

🤔 What's changed?

When writing output, Reqnroll only uses TestContext and don't write to Console.
The same happens already for NUnit and xUnit.

⚡️ What's your motivation?

Fixes #298

This avoids duplicate output and that Console output of tests get mixed up.

🏷️ What kind of change is this?

• 🐛 Bug fix (non-breaking change which fixes a defect)

♻️ Anything particular you want feedback on?

Is there a particular reason why currently both TestContext and Console output is used?

📋 Checklist:

• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes. (see unit test changes)
• Users should know about my change
  • I have added an entry to the "[vNext]" section of the CHANGELOG, linking to this pull request & included my GitHub handle to the release contributors list.

[Code-Grump]

Clean and simple. Love it.