Fix testSequenceBuilder() failing test on Windows (#32970)

The previous "cleanup" commit to instead use
PHP_EOL was a breaking change. This test case
reads tests/Http/Fixtures/test.txt which always
has a "\n" line ending.

Author: derekmd

tests/Http/HttpClientTest.php

@@ -250,7 +250,7 @@ public function testSequenceBuilder()
         $this->assertSame(200, $response->status());
 
         $response = $this->factory->get('https://example.com');
-        $this->assertSame('This is a story about something that happened long ago when your grandfather was a child.'.PHP_EOL, $response->body());
+        $this->assertSame("This is a story about something that happened long ago when your grandfather was a child.\n", $response->body());
         $this->assertSame(200, $response->status());
 
         $response = $this->factory->get('https://example.com');