chore: migrate $ERROR -> throw new Test262Error in .jshintrc, harness/sta.js (#3122)

.jshintrc

@@ -1,3 +1,3 @@
 {
-    "predef": ["$ERROR", "Intl"]
+    "predef": ["Intl"]
 }

harness/sta.js

@@ -6,7 +6,7 @@ description: |
 
     - An error class to avoid false positives when testing for thrown exceptions
     - A function to explicitly throw an exception using the Test262Error class
-defines: [Test262Error, $ERROR, $DONOTEVALUATE]
+defines: [Test262Error, $DONOTEVALUATE]
 ---*/
 
 
@@ -21,8 +21,6 @@ Test262Error.prototype.toString = function () {
 Test262Error.thrower = (message) => {
   throw new Test262Error(message);
 };
-// TODO: Remove when $ERROR migration is completed
-var $ERROR = Test262Error.thrower;
 
 function $DONOTEVALUATE() {
   throw "Test262: This statement should not be evaluated.";