Add missing SKIPIF clauses to new test cases

Author: cmb69

ext/phar/tests/bug69279.phpt

@@ -3,6 +3,7 @@ Bug #69279 (Compressed ZIP Phar extractTo() creates garbage files)
 --SKIPIF--
 <?php
 if (!extension_loaded('phar')) die('skip phar extension not available');
+if (!extension_loaded('zlib')) die('skip zlib extension not available');
 ?>
 --INI--
 phar.readonly=0

ext/phar/tests/bug79912.phpt

@@ -3,6 +3,7 @@ Bug #79912 (Phar::decompressFiles not working)
 --SKIPIF--
 <?php
 if (!extension_loaded('phar')) die('skip phar extension is not available');
+if (!extension_loaded('zlib')) die('skip zlib extension not available');
 ?>
 --INI--
 phar.readonly=0