jsonnet-lint hangs under certain conditions

OK, I'm down to one file that jsonnet-lint refuses to process. It basically hangs and ultimately gets killed by what I'm assuming is an OOM killer on my Mac. The weird thing is that _sometimes_ it will return just fine in sub-second.

That file has all sorts of proprietary stuff in it so I've tried my best to create a repro test case but you'll have to tell me if it worked :)

* Clone this repo: https://github.com/gotwarlost/jsonnet-lint-issues
* run `bash-loop.sh` - it should show you processing times increase as the number of keys in the `caller.jsonnet` map increases and will eventually reach a point where jsonnet-lint doesn't return.

I've no idea what's going but it feels like some sort of quadratic/ exponential processing, or some lock contention. As I mentioned, the weird part is that every so often it will return just fine.