test: remove unneeded code

Author: kenjis

tests/system/HTTP/MessageTest.php

@@ -30,12 +30,6 @@ protected function setUp(): void
         $this->message = new Message();
     }
 
-    protected function tearDown(): void
-    {
-        $this->message = null;
-        unset($this->message);
-    }
-
     // We can only test the headers retrieved from $_SERVER
     // This test might fail under apache.
     public function testHeadersRetrievesHeaders()
@@ -256,7 +250,6 @@ public function testPopulateHeadersWithoutContentType()
 
         $this->assertNull($this->message->header('content-type'));
         putenv("CONTENT_TYPE={$originalEnv}");
-        $this->message->removeHeader('accept-language');
 
         $_SERVER = $original; // restore so code coverage doesn't break
     }
@@ -290,7 +283,6 @@ public function testPopulateHeadersKeyNotExists()
         $this->message->populateHeaders();
 
         $this->assertSame('', $this->message->header('accept-charset')->getValue());
-        $this->message->removeHeader('accept-charset');
 
         $_SERVER = $original; // restore so code coverage doesn't break
     }
@@ -308,8 +300,6 @@ public function testPopulateHeaders()
 
         $this->assertSame('text/html; charset=utf-8', $this->message->header('content-type')->getValue());
         $this->assertSame('en-us,en;q=0.50', $this->message->header('accept-language')->getValue());
-        $this->message->removeHeader('content-type');
-        $this->message->removeHeader('accept-language');
 
         $_SERVER = $original; // restore so code coverage doesn't break
     }