Skip tests under asan

When PDO firebird is loaded and these posix tests are run with
parallelism, LeakSanitizer will occasionally segfault. I was not
able to root cause this issue, as I failed to reproduce it in
simpler circumstances. I don't think it's an issue on our side
though.

Author: nikic

ext/posix/tests/posix_getgrgid_error.phpt

@@ -2,7 +2,8 @@
 Test posix_getgrgid() function : error conditions
 --SKIPIF--
 <?php
-    if(!extension_loaded("posix")) print "skip - POSIX extension not loaded";
+if(!extension_loaded("posix")) die("skip - POSIX extension not loaded");
+if (getenv('SKIP_ASAN')) die('skip LSan crashes when firebird is loaded');
 ?>
 --FILE--
 <?php

ext/posix/tests/posix_getpwuid_error.phpt

@@ -2,7 +2,8 @@
 Test posix_getpwuid() function : error conditions
 --SKIPIF--
 <?php
-    if(!extension_loaded("posix")) print "skip - POSIX extension not loaded";
+if(!extension_loaded("posix")) dir("skip - POSIX extension not loaded");
+if (getenv('SKIP_ASAN')) die('skip LSan crashes when firebird is loaded');
 ?>
 --FILE--
 <?php