MAGETWO-69137: upgrading Magento2 Project PHPUnit version to latest

 - changed unit tests to support PHPUnit 6.2

Author: Robert He

dev/tests/integration/testsuite/Magento/User/Controller/Adminhtml/AuthTest.php

@@ -267,10 +267,9 @@ public function testResetPasswordPostActionWithInvalidPassword()
      */
     protected function prepareEmailMock($occurrenceNumber, $templateId, $sender)
     {
-        $transportMock = $this->createPartialMock(
-            \Magento\Framework\Mail\TransportInterface::class,
-            ['sendMessage']
-        );
+        $transportMock = $this->getMockBuilder(\Magento\Framework\Mail\TransportInterface::class)
+            ->setMethods(['sendMessage'])
+            ->getMockForAbstractClass();
         $transportMock->expects($this->exactly($occurrenceNumber))
             ->method('sendMessage');
         $transportBuilderMock = $this->getMockBuilder(\Magento\Framework\Mail\Template\TransportBuilder::class)