Test migration to jest by hand

Apparently using regular expressions is way easier.

test/dropRightWhile/dropRightWhile.js

@@ -0,0 +1,5 @@
+const dropRightWhile = (arr, func) => {
+while (arr.length > 0 && !func(arr[arr.length - 1])) arr = arr.slice(0, -1);
+return arr;
+};
+module.exports = dropRightWhile;