JS: Add: test cases for toWellFormed

Author: Napalys

javascript/ql/test/library-tests/TaintTracking/string-immutable-operations.js

@@ -0,0 +1,12 @@
+function test() {
+    let x = source();
+    sink(x.toWellFormed()); // NOT OK -- Currently not tainted, but should be
+
+    const wellFormedX = x.toWellFormed();
+    sink(wellFormedX); // NOT OK -- Currently not tainted, but should be
+
+    const concatWellFormedX = "/" + wellFormedX + "!";
+    sink(concatWellFormedX); // NOT OK -- Currently not tainted, but should be
+
+    sink(source().toWellFormed()); // NOT OK -- Currently not tainted, but should be
+}