Fix PHPUnit deprecation warnings.

Author: markstory

tests/TestCase/Cache/Engine/DebugEngineTest.php

@@ -42,7 +42,7 @@ class DebugEngineTest extends TestCase
     public function setUp()
     {
         parent::setUp();
-        $mock = $this->getMock('Cake\Cache\CacheEngine');
+        $mock = $this->getMockBuilder('Cake\Cache\CacheEngine')->getMock();
         $this->mock = $mock;
         $this->engine = new DebugEngine($mock);
         $this->engine->init();

tests/TestCase/Controller/ToolbarControllerTest.php

@@ -69,7 +69,7 @@ public function testClearCacheNoGet()
      */
     public function testClearCache()
     {
-        $mock = $this->getMock('Cake\Cache\CacheEngine');
+        $mock = $this->getMockBuilder('Cake\Cache\CacheEngine')->getMock();
         $mock->expects($this->once())
             ->method('init')
             ->will($this->returnValue(true));

tests/TestCase/Database/Log/DebugLogTest.php

@@ -69,7 +69,7 @@ public function testLog()
      */
     public function testLogDecorates()
     {
-        $orig = $this->getMock('Cake\Database\Log\QueryLogger');
+        $orig = $this->getMockBuilder('Cake\Database\Log\QueryLogger')->getMock();
         $orig->expects($this->once())
             ->method('log');