Added underscore.string test cases for str to array.

Author: Napalys

javascript/ql/test/library-tests/TripleDot/underscore.string.js

@@ -33,3 +33,10 @@ function strToStr() {
   sink(s.unquote(source("s30"), "quote")); // $ hasTaintFlow=s30
   sink(s.map(source("s31"), (x) => {return x;})); // $ hasTaintFlow=s31
 }
+
+function strToArray() {
+  sink(s.chop(source("s1"), 3)[0]); // $ MISSING: hasTaintFlow=s1
+  sink(s.chars(source("s2")[0])); // $ MISSING:  hasTaintFlow=s2
+  sink(s.words(source("s3")[0])); // $ MISSING: hasTaintFlow=s3
+  sink(s.lines(source("s7")[0])); // $ MISSING: hasTaintFlow=s7
+}