MDL-62241 privacy: Include the unit tests from the 3.3 branch

The tests do not actually do anything, they just make sure that the
method signature is correct on the given PHP version. They are mostly
relevant and useful on 3.3.

privacy/tests/manager_test.php

@@ -213,4 +213,18 @@ class privacy_manager_testcase extends advanced_testcase {
         $this->expectException(\coding_exception::class);
         $string = $manager->get_null_provider_reason('mod_testcomponent');
     }
+
+    /**
+     * Test that manager::plugintype_class_callback() can be executed.
+     */
+    public function test_plugintype_class_callback() {
+        \core_privacy\manager::plugintype_class_callback('doesnotexist', 'unusable', 'foo', ['bar']);
+    }
+
+    /**
+     * Test that manager::component_class_callback() can be executed.
+     */
+    public function test_component_class_callback() {
+        \core_privacy\manager::component_class_callback('foo_bar', 'unusable', 'foo', ['bar']);
+    }
 }