minor symfony#52316 [Process] remove fixing of legacy bug, when PTS functionality is enabled (a.dmitryuk)

This PR was squashed before being merged into the 6.4 branch.

Discussion
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[Process] remove fixing of legacy bug, when PTS functionality is enabled

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Issues        |
| License       | MIT

The PR drop fixing PHP bug, that was closed in PHP 7.0

Original issues:
php/php-src#1588
symfony#16574

Original commit:
php/php-src@ff6b309

Commits
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03590f1 [Process] remove fixing of legacy bug, when PTS functionality is enabled

Author: nicolas-grekas

src/Symfony/Component/Process/Process.php

@@ -332,10 +332,6 @@ public function start(callable $callback = null, array $env = [])
             // See https://unix.stackexchange.com/questions/71205/background-process-pipe-input
             $commandline = '{ ('.$commandline.') <&3 3<&- 3>/dev/null & } 3<&0;';
             $commandline .= 'pid=$!; echo $pid >&3; wait $pid 2>/dev/null; code=$?; echo $code >&3; exit $code';
-
-            // Workaround for the bug, when PTS functionality is enabled.
-            // @see : https://bugs.php.net/69442
-            $ptsWorkaround = fopen(__FILE__, 'r');
         }
 
         $envPairs = [];