Improve memory efficiency

This avoids concatenating `$message` and `PHP_EOL` (if necessary) as a new value, greatly improving memory efficiency for large `$message`s.

src/Symfony/Component/Console/Output/StreamOutput.php

@@ -70,7 +70,7 @@ class StreamOutput extends Output
      */
     protected function doWrite($message, $newline)
     {
-        if (false === @fwrite($this->stream, $message.($newline ? PHP_EOL : ''))) {
+        if (false === @fwrite($this->stream, $message) || ($newline && (false === @fwrite($this->stream, PHP_EOL)))) {
             // should never happen
             throw new \RuntimeException('Unable to write output.');
         }