Added Additional Test to Increment a Number

Added an additional test to check that myVar = myVar is not still
present. Tested locally.

challenges/01-front-end-development-certification/basic-javascript.json

@@ -443,6 +443,7 @@
       ],
       "tests": [
         "assert(myVar === 88, 'message: <code>myVar</code> should equal <code>88</code>');",
+        "assert(/myVar\\s*\\=.*myVar/.test(code) === false, 'message: <code>myVar = myVar</code> should be changed');",
         "assert(/myVar\\s*[+]{2}/.test(code), 'message: Use the <code>++</code> operator');",
         "assert(/var myVar = 87;/.test(code), 'message: Do not change code above the line');"
       ],