[HttpFoundation] fixed a unit tests

tests/Symfony/Tests/Component/HttpFoundation/ResponseTest.php

@@ -184,9 +184,6 @@ class ResponseTest extends \PHPUnit_Framework_TestCase
             ->method('set')
             ->with('Content-Type', 'text/html; charset=UTF-8');
         $headerMock->expects($this->at(1))
-            ->method('set')
-            ->with('Content-Length', '3');
-        $headerMock->expects($this->at(2))
             ->method('set')
             ->with('Content-Type', 'text/html; charset=Foo');
 

tests/Symfony/Tests/Component/HttpKernel/HttpCache/HttpCacheTest.php

@@ -100,7 +100,6 @@ class HttpCacheTest extends HttpCacheTestCase
 
         $this->assertHttpKernelIsCalled();
         $this->assertEquals(304, $this->response->getStatusCode());
-        $this->assertSame(0, $this->response->headers->get('Content-Length'));
         $this->assertEquals('text/html; charset=UTF-8', $this->response->headers->get('Content-Type'));
         $this->assertEmpty($this->response->getContent());
         $this->assertTraceContains('miss');
@@ -114,7 +113,6 @@ class HttpCacheTest extends HttpCacheTestCase
 
         $this->assertHttpKernelIsCalled();
         $this->assertEquals(304, $this->response->getStatusCode());
-        $this->assertSame(0, $this->response->headers->get('Content-Length'));
         $this->assertEquals('text/html; charset=UTF-8', $this->response->headers->get('Content-Type'));
         $this->assertTrue($this->response->headers->has('ETag'));
         $this->assertEmpty($this->response->getContent());