closes https://github.com/oxc-project/oxc/issues/4790
@overlookmotel enjoy ... take a look at the snapshots and probably nothing else.
The snapshots are minimal right now, but it's already showing symbols from import specifiers are not being removed. We can iterate on the snapshot representation to aid debugging later.
I'll extend this to `transformer_conformance` and `oxc-monitor` in an up coming PR.
Move `BabelOptions` to Transformer. The `output.json` is a standard babel configuration. We can reuse BabelOptions to read [babel.config.json](https://babeljs.io/docs/configuration#babelconfigjson) or our configuration(maybe oxc.config.json)
The current `from_babel_options` implementation is copied from the `transform_options` in `test_case.rs`, which I'll completely reimplement next
If submodules are outdated, it'll panic with the following message
```
Repository is outdated, please run `just submodules` to update it.
```
For us maintainers, we'll need the env `UPDATE_SNAPSHOT` to force an update.
