Resolved formatting issues in test command output

[matthewnitschke-wk]

The new test command introduced in this PR contained some issues when rendering the failure list.

Upon failure, this is what the output would look like

✗ lib/functions.dart
    Failure - row: 2, column: 2
      Expected: 'definition asdf'
      Actual:
        - 'reference scip-dart pub scip_dart_test 1.0.0 lib/`functions.dart`/withReturn().'
        - 'diagnostic Information'
          ''withReturn' is deprecated and shouldn't be used. a.'    Failure - row: 14, column: 2
      Expected: 'reference scip-dart pub dart:core 2.19.0 dart:core/`int.dart`/int#'
      Actual:
        - 'reference scip-dart pub dart:core 2.19.0 dart:core/`int.dart`/int#'✗ Missing documents in SCIP index
    test/.dart_tool/package_config.json
    test/pubspec.lock
    test/pubspec.yaml

After this change, the output now looks like this

✗ lib/functions.dart
    Failure [Ln: 3, Col: 2]
      Expected: 'definition asdf'
      Actual: * 'reference scip-dart pub scip_dart_test 1.0.0 lib/`functions.dart`/withReturn().'
              * 'diagnostic Information'
                ''withReturn' is deprecated and shouldn't be used. a.'
    Failure [Ln: 15, Col: 2]
      Expected: 'reference scip-dart pub dart:core 2.19.0 dart:core/`int.dart`/int#'
      Actual:   'reference scip-dart pub dart:core 2.19.0 dart:core/`int.dart`/int#'
✗ Missing documents in SCIP index
    test/.dart_tool/package_config.json
    test/pubspec.lock
    test/pubspec.yaml

Notable updates being:

• The line break after the last failure in a test file has been resolved
• The Expected vs Actual lines are on the same column, making it easier to locate inconsistencies
• Mutli-result "Actual" statements are now prefixed with a *, to indicate they are "one of many". This also helps delineate multiline test attributes

[varungandhi-src]

Hey, sorry we missed merging this earlier. Please feel free to tag me directly for PR reviews.