MDL-32323 prevent modification of our heavily modified runBare() methods

This should help with compatibility of future PHPUnit and it also allows us to improve test reset without breaking existing moodle test cases.

lib/phpunit/lib.php

@@ -1001,7 +1001,7 @@ class basic_testcase extends PHPUnit_Framework_TestCase {
      * Runs the bare test sequence and log any changes in global state or database.
      * @return void
      */
-    public function runBare() {
+    final public function runBare() {
         global $DB;
 
         try {
@@ -1058,7 +1058,7 @@ class advanced_testcase extends PHPUnit_Framework_TestCase {
      * Runs the bare test sequence.
      * @return void
      */
-    public function runBare() {
+    final public function runBare() {
         global $DB;
 
         if (phpunit_util::$lastdbwrites != $DB->perf_get_writes()) {