Fix infinite loop and undefined behavior in del(.[nan]) (#3490)

tests/jq.test

@@ -1176,6 +1176,14 @@ del(.[1], .[-6], .[2], .[-3:9])
 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
 [0, 3, 5, 6, 9]
 
+del(.[nan])
+[1,2,3]
+[1,2,3]
+
+del(.[nan,nan])
+[1,2,3]
+[1,2,3]
+
 # negative index
 setpath([-1]; 1)
 [0]