Pass path to a dynamically imported file as file:// protocol URL to make it work in Windows

[psmyrek]

Suggested merge commit message (convention)

Fix (release-tools): Fixed path calculation in executeInParallel() util that prepares a path to a dynamically imported worker script. Previously, it did not work in Windows, because there is a specific requirement that absolute path must be valid file:// protocol URL. Now, the worker script is always imported using file:// protocol URL.

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Additional information

Closes cksource/ckeditor5-internal#3882.

I'm not using url.pathToFileURL() to convert the path to a file:// protocol URL, because it produces unexpected results in tests where we mock process.cwd() to be Windows-style.

Example: when mocked process.cwd() is C:\Users\ckeditor, then url.pathToFileURL( 'C:/Users/ckeditor/uuid-4.mjs' ) internally tries to create an URL from file://C:%5CUsers%5Cckeditor/C:/Users/ckeditor/uuid-4.mjs and throws ERR_INVALID_URL.

[pomek]

I would like to use pathToFileURL(), but I assume you tried it, and it did not work.

So, let's use the proposed solution. LGTM.