Streamline test results storage folder

[kennyadsl]

Description

For Solidus Starter Frontend, there's no need to use a dynamically named folder because each combination will run in a separate job.

This was needed on extensions when the combination of solidus versions was run as different tasks on the same job.

Ref #308

Motivation and Context

To see tests results in the CircleCI interface.

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.