Update IntegrationTestCase::_buildRequest

Hi,

I'm not sure it's the better way to do this but, the method is currently not use in this method.
I'm tried to test my controller. #4606

When i used __$this->put('/actions/changeStatus/1.json', ['status_id' => 2])__. But on the action of the controller, the request don't have a variable environment __REQUEST_METHOD__.

So these lines above resolve this problem.

Jason.

src/TestSuite/IntegrationTestCase.php

@@ -320,14 +320,15 @@ protected function _buildRequest($url, $method, $data) {
 			'cookies' => $this->_cookie,
 			'session' => $session,
 		];
+		$env[];
 		if (isset($this->_request['headers'])) {
-			$env = [];
 			foreach ($this->_request['headers'] as $k => $v) {
 				$env['HTTP_' . str_replace('-', '_', strtoupper($k))] = $v;
 			}
-			$props['environment'] = $env;
 			unset($this->_request['headers']);
 		}
+		$env['REQUEST_METHOD'] = $method;
+		$props['environment'] = $env;
 		$props += $this->_request;
 		return new Request($props);
 	}