MDL-67673 phpunit: Fix the return type of template methods

All the setup/teardown/pre/post/conditions template methods
now are required to return void. This was warned with phpunit 7
and now is enforced.

At the same time, fix a few wrong function names,
provider data and param types, return statements...

auth/email/tests/external_test.php

@@ -43,7 +43,7 @@ class auth_email_external_testcase extends externallib_advanced_testcase {
     /**
      * Set up for every test
      */
-    public function setUp() {
+    public function setUp(): void {
         global $CFG, $DB;
 
         $this->resetAfterTest(true);

auth/manual/tests/manual_test.php

@@ -44,7 +44,7 @@ class auth_manual_testcase extends advanced_testcase {
     /**
      * Setup test data.
      */
-    protected function setUp() {
+    protected function setUp(): void {
         $this->resetAfterTest(true);
         $this->authplugin = new auth_plugin_manual();
         set_config('expiration', '1', 'auth_manual');

auth/manual/tests/privacy_provider_test.php

@@ -45,7 +45,7 @@ class auth_manual_privacy_testcase extends \core_privacy\tests\provider_testcase
     /**
      * Basic setup for these tests.
      */
-    public function setUp() {
+    public function setUp(): void {
         $this->resetAfterTest(true);
         $this->authplugin = new auth_plugin_manual();
     }

auth/mnet/tests/privacy_provider_test.php

@@ -43,7 +43,7 @@ class auth_mnet_privacy_testcase extends provider_testcase {
     /**
      * Set up method.
      */
-    public function setUp() {
+    public function setUp(): void {
         $this->resetAfterTest();
         $this->setAdminUser();
     }

auth/oauth2/tests/privacy_provider_test.php

@@ -42,7 +42,7 @@ class auth_oauth2_privacy_testcase extends provider_testcase {
     /**
      * Set up method.
      */
-    public function setUp() {
+    public function setUp(): void {
         $this->resetAfterTest();
         $this->setAdminUser();
     }

auth/tests/external_test.php

@@ -46,7 +46,7 @@ class core_auth_external_testcase extends externallib_advanced_testcase {
     /**
      * Set up for every test
      */
-    public function setUp() {
+    public function setUp(): void {
         global $CFG;
 
         $this->resetAfterTest(true);
@@ -60,7 +60,7 @@ class core_auth_external_testcase extends externallib_advanced_testcase {
     /**
      * Tear down to restore old logging..
      */
-    protected function tearDown() {
+    protected function tearDown(): void {
         ini_set('error_log', $this->oldlog);
         parent::tearDown();
     }

auth/tests/privacy_test.php

@@ -43,7 +43,7 @@ use core_auth\privacy\provider;
  */
 class core_auth_privacy_testcase extends provider_testcase {
 
-    public function setUp() {
+    public function setUp(): void {
         $this->resetAfterTest();
     }