Fix Reference Error for module.exports in browser environment

[BeNikk]

Description

Fixes #4228
This PR addresses a ReferenceError that occurred in browser environments due to the usage of module.exports without checking for its existence. The issue arises because module.exports is specific to Node.js/CommonJS environments and is not defined in browsers.

Solution

The fix introduces a conditional check to ensure module.exports is only assigned when the module object is defined (i.e., in Node.js/CommonJS environments). In browser environments, the export does nothing, avoiding the ReferenceError.
This solution works because before introducing the tests in musicblocks repository, we were not exporting any module, so the solution does not break anything.

Testing

The code changes make sure that all the tests still run fine.

Browser error

The browser does not throw any reference error now

[BeNikk]

@walterbender I think this can be a fix for all the reference errors, might be a simple solution but solves the issue.