Make `fix` sub-command test suite pass on Windows

[Gedochao]

Version(s)
94a6e37

Describe the bug
A lot of tests of the fix sub-command seem to fail on Windows CI for unknown reasons, with errors similar to:

 os.SubprocessException: Result of D:\a\scala-cli\scala-cli\out\integration\test\forcedLauncher.dest\scala-cli.exe�: 256

Unsure if it is an actual problem, or merely something tied to the CI and/or tests, needs investigation.

To Reproduce

• Ensure test source directives with test scope equivalents are migrated by fix to project.scala #3425 (comment)
• Don't migrate directives with fix for single-file projects #3422 (comment)
• fix built-in rules: don't wrap directive values in double quotes if not necessary #3414 (comment)

Expected behaviour
Should run on Windows without failures.