Set return type of base TestCase methods

From the [PHPUnit 8 release notes][1], the `TestCase` methods below now declare a `void` return type:

- `setUpBeforeClass()`
- `setUp()`
- `assertPreConditions()`
- `assertPostConditions()`
- `tearDown()`
- `tearDownAfterClass()`
- `onNotSuccessfulTest()`

[1]: https://phpunit.de/announcements/phpunit-8.html

Author: laravel-shift

tests/ToolkitApiTest/ToolkitServiceParameterTest.php

@@ -25,7 +25,7 @@ final class ProgramParameterTest extends TestCase
     protected $dim;
     protected $by;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->size = 20;
         $this->type = sprintf('%dB', $this->size);
@@ -168,7 +168,7 @@ final class BinParamTest extends TestCase
      */
     protected $programParameter;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $size = 20;
         $this->binParam = new BinParam('both', $size, 'UncodeSample', 'p1', 'test');

tests/ToolkitApiTest/ToolkitTest.php

@@ -35,7 +35,7 @@ final class ToolkitTest extends TestCase
      */
     protected $toolkit;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->toolkit = new Toolkit('*LOCAL', '0', 'testPwd', 'http', false);
     }

tests/functional/ToolkitTest.php

@@ -21,7 +21,7 @@ final class ToolkitTest extends TestCase
      */
     private $toolkitOptions;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $config = getConfig();