Use shell-free proc_open() in parallel run-tests.php

Author: nikic

run-tests.php

@@ -1451,7 +1451,7 @@ function run_all_tests_parallel(array $test_files, array $env, $redir_tested): v
     $startTime = microtime(true);
     for ($i = 1; $i <= $workers; $i++) {
         $proc = proc_open(
-            $thisPHP . ' ' . escapeshellarg($thisScript),
+            [$thisPHP, $thisScript],
             [], // Inherit our stdin, stdout and stderr
             $pipes,
             null,