[Meteor 3] Very slow namespace imports when at least two in same module

In Meteor 3, this code is very slow on the client (it probably takes at least 20 seconds to finish). I didn't check how it performs on Meteor 2.

```js
import * as R from 'react';
import * as a from '@mui/icons-material';
```

Having either one of the two imports is fine. The problem only happens when there are both.