Make bug70417.phpt less flaky

Closes phpGH-20287.

Author: ndossche

ext/phar/tests/tar/bug70417.phpt

@@ -3,32 +3,17 @@ Bug #70417 (PharData::compress() doesn't close temp file)
 --EXTENSIONS--
 phar
 zlib
---SKIPIF--
-<?php
-
-exec('lsof -p ' . getmypid(), $out, $status);
-if ($status !== 0) {
-    die("skip lsof(8) not available");
-}
-if (!str_starts_with($out[0], 'COMMAND')) {
-    die("skip Might be a different lsof");
-}
-?>
 --FILE--
 <?php
-function countOpenFiles() {
-    exec('lsof -p ' . escapeshellarg(getmypid()) . ' 2> /dev/null', $out);  // Note: valgrind can produce false positives for /usr/bin/lsof
-    return count($out);
-}
 $filename = __DIR__ . '/bug70417.tar';
 @unlink("$filename.gz");
-$openFiles1 = countOpenFiles();
+$resBefore = count(get_resources());
 $arch = new PharData($filename);
 $arch->addFromString('foo', 'bar');
 $arch->compress(Phar::GZ);
 unset($arch);
-$openFiles2 = countOpenFiles();
-var_dump($openFiles1 === $openFiles2);
+$resAfter = count(get_resources());
+var_dump($resBefore === $resAfter);
 ?>
 --CLEAN--
 <?php