negative index on empty arrays gives index out of bound instead of giving null output. #77

jsonata: [][-1]
js output: ** no match **
java output: Index -1 out of bounds for length 0

jsonata: [][1]
js output: ** no match **
java output: null

input json:{"item": []}

jsonata: item[-1]
js output: ** no match **
java output:Index -1 out of bounds for length 0

jsonata: item[-2]
js output: ** no match **
java output:Index -2 out of bounds for length 0

jsonata: item[0]
js output: ** no match **
java output:null

jsonata: item[1]
js output: ** no match **
java output:null

positive indexes looks good. but on accessing negative indexes, instead of resulting in null, exception IndexOutOfBound is thrown.