fix: support imports of absolute paths of ESM files on Windows

[giladgd]

Description of change

Support importing absolute paths of ESM file on Windows.

For example, this code would work now:

import {importOrRequireFile} from "./util/ImportUtils";

await importOrRequireFile("./index.mjs");
await importOrRequireFile("./index.cjs");

// on macOS / Linux
await importOrRequireFile("/Users/user/Documents/index.mjs");
await importOrRequireFile("/Users/user/Documents/index.cjs");

// on Windows
await importOrRequireFile("C:\\Users\\user\\Documents\\index.mjs"); // this line previously thrown an error, this PR fixes that
await importOrRequireFile("C:\\Users\\user\\Documents\\index.cjs");

Closes #8651

Pull-Request Checklist

• Code is up-to-date with the master branch
• npm run lint passes with this change
• npm run test passes with this change
• This pull request links relevant issues as Fixes #0000
• There are new or updated unit tests validating the change - The best way to test this code would be to run tests also on a Windows machine which would catch issue like this one, but I guess this is out of scope for the issue
• Documentation has been updated to reflect this change
• The new commits follow conventions explained in CONTRIBUTING.md

[pleerock]

Thanks a lot!