Add missing extension dependencies for tests

ext/pdo_pgsql/tests/transations_deprecations.phpt

@@ -1,5 +1,7 @@
 --TEST--
 Test PDO::PGSQL_TRANSACTION* constants.
+--EXTENSIONS--
+pdo
 --SKIPIF--
 <?php
 if (substr(PHP_OS, 0, 3) == 'WIN') {

ext/phar/tests/gh19752.phpt

@@ -1,5 +1,7 @@
 --TEST--
 GH-19752 (Phar decompression with invalid extension can cause UAF)
+--EXTENSIONS--
+phar
 --FILE--
 <?php
 $phar = new PharData(__DIR__.'/gh19752.1');

ext/simplexml/tests/gh15837.phpt

@@ -2,6 +2,8 @@
 GH-15837 (Segmentation fault in ext/simplexml/simplexml.c)
 --CREDITS--
 YuanchengJiang
+--EXTENSIONS--
+simplexml
 --FILE--
 <?php
 $xml =<<<EOF