fix #222 - Windows NO_COVERAGE issue

[vivganes]

Proposed changes

This PR fixes #222

Root Cause: Path separators were not handled properly, which resulted in Windows coverage always calculated as NOT COVERED for all mutants

Types of changes

• Bugfix (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)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• Lint and unit tests pass locally with my changes (make all)
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in downstream modules

Further comments

None

[vivganes]

@k3rn31 can you please take a look at this PR? Please let me know if you need any more information

[vivganes]

@k3rn31 the automated checks seem to be stuck due to some reason even after your approval. Do these checks need any other condition to be fulfilled???