saveObject writes into wrong environment

[godmar]

If comp is the default env, and test_drivebase is selected, and no file "XConstants.json" exists, then jsonHandler.saveObject(_) writes into comp.

However, if you touch a zero-byte file in test_drivebase, it's written there.

[godmar]

The current behavior essentially applies the same "fallback" strategy to writing as it does to reading. That is, if no file exists in the current env, it'll fall back to the default env. However, while this makes sense for reading, it really does not make sense for writing. If we select an env for tuning and save it, we need it to stay in this env and not create a file in the default env. So this needs fixing.