Need test for filter expression checking for local key in array with a null value

[gregsdennis]

A coworker stumbled on this.

jsonpath-plus seems to error for this case

Path: $[?(@.key == 'value')
Data: [ 5, "value", null, "other value", false ]

It seems when @.key is evaluated and @ is null, the implementation throws an error instead of just returning an empty nodelist.