Add tests to es6 challenge Write Higher Order Arrow Functions. Doesn't have es6 syntax tests.

Comments out function and arrow tests that didn't work and fixes formatting issues.

challenges/02-javascript-algorithms-and-data-structures/es6.json

@@ -265,14 +265,14 @@
         "console.log(squaredIntegers);"
       ],
       "tests": [
-        "// Test user did replace var keyword",
+        "// Test user did replace <code>var</code> keyword",
-        "// Test squaredIntegers is const",
+        "// Test <code>squaredIntegers</code> is <code>const</code>",
-        "// Test squaredIntegers is an array",
+        "assert(Array.isArray(squaredIntegers), 'message: <code>squaredIntegers</code> should be an array');",
-        "// Test squaredIntegers is [16, 1764, 36]",
+        "assert(squaredIntegers[0] === 16 && squaredIntegers[1] === 1764 && squaredIntegers[2] === 36, 'message: <code>squaredIntegers</code> should be <code>[16, 1764, 36]</code>');",
-        "// Test function keyword was not used",
+        "// Test <code>function</code> keyword was not used",
-        "// Test arrow => was used",
+        "// Test arrow <code>=></code> was used",
-        "// Test loop was not used",
+        "assert(!code.match(/(for)|(while)/g), 'message: loop should not be used');",
-        "// Test map and filter were used"
+        "assert(code.match(/map/g) && code.match(/filter/g), 'message: <code>map</code> and <code>filter</code> should be used');"
       ],
       "type": "waypoint",
       "releasedOn": "Feb 17, 2017",