Make errors in native functions runtime errors
Make errors in native functions runtime errors

Instead of crashing with internal error

sbarzowski/go-jsonnet,sbarzowski/go-jsonnet,sbarzowski/go-jsonnet,sbarzowski/go-jsonnet,google/go-jsonnet,google/go-jsonnet,sbarzowski/go-jsonnet,google/go-jsonnet,google/go-jsonnet,google/go-jsonnet