Fix directory collisions in zlib tests

Author: nikic

ext/zlib/tests/gzfile_variation15.phpt

@@ -8,6 +8,7 @@ if (!extension_loaded("zlib")) {
 ?>
 --FILE--
 <?php
+$thisTestDir = 'gzfile_variation15.dir';
 require_once('reading_include_path.inc');
 
 //define the files to go into these directories, create one in dir2

ext/zlib/tests/gzopen_variation4.phpt

@@ -16,6 +16,7 @@ if (!extension_loaded("zlib")) {
 
 echo "*** Testing gzopen() : usage variation ***\n";
 
+$thisTestDir = 'gzopen_variation4.dir';
 require_once('reading_include_path.inc');
 
 //define the files to go into these directories, create one in dir2

ext/zlib/tests/readgzfile_variation15.phpt

@@ -8,6 +8,7 @@ if (!extension_loaded("zlib")) {
 ?>
 --FILE--
 <?php
+$thisTestDir = 'readgzfile_variation15.dir';
 require_once('reading_include_path.inc');
 
 //define the files to go into these directories, create one in dir2

ext/zlib/tests/reading_include_path.inc

@@ -1,5 +1,4 @@
 <?php
-$thisTestDir = "zlibVariation.dir";
 mkdir($thisTestDir);
 chdir($thisTestDir);