[skip ci] Mark some more macOS tests as flaky

Author: iluuu1994

ext/posix/tests/posix_getgrnam_basic.phpt

@@ -4,7 +4,10 @@ Test posix_getgrnam() function : basic functionality
 posix
 --SKIPIF--
 <?php
-    if (!posix_getgroups()) die('skip - groups unavailable (ci)');
+if (!posix_getgroups()) die('skip - groups unavailable (ci)');
+if (getenv("GITHUB_ACTIONS") && PHP_OS_FAMILY === "Darwin") {
+    die("flaky Occasionally segfaults on macOS for unknown reasons");
+}
 ?>
 --FILE--
 <?php

ext/posix/tests/posix_getgroups_basic.phpt

@@ -2,6 +2,12 @@
 Test posix_getgroups() function : basic functionality
 --EXTENSIONS--
 posix
+--SKIPIF--
+<?php
+if (getenv("GITHUB_ACTIONS") && PHP_OS_FAMILY === "Darwin") {
+    die("flaky Occasionally segfaults on macOS for unknown reasons");
+}
+?>
 --FILE--
 <?php
   echo "Basic test of POSIX getgroups\n";