fix(modern-module): use module style export for non entry module

[fi3ework]

Summary

• If the variable to be exported is not in the inlined module (commonly triggered by async modules), should use the "module" style export way to export it.
• Deleted the test cases of library in rspack test which are duplicated with existing webpack test.
• Remove -- from testu command, I do not know when it became redundant and will fail the command.

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

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[LingyuCoder]

The -- -u in testu works well for me. It only works when using npm run testu. If you use pnpm run testu, the -- will be converted to "--" and then the test will regard it as a path and run without any test cases. Perhaps we can use a bash script for compatibility.

[fi3ework]

The -- -u in testu works well for me. It only works when using npm run testu. If you use pnpm run testu, the -- will be converted to "--" and then the test will regard it as a path and run without any test cases. Perhaps we can use a bash script for compatibility.

The newer version (6.2.1, we're using 6.2.0) of npm-run-all2 has fix the -- dilemma https://redirect.github.com/bcomnes/npm-run-all2/pull/143. I'll launch a new PR to fix this. Revert the change in this PR.