Clean up some more function_exists() checks

ext/xmlwriter/tests/005-mb.phpt

@@ -2,10 +2,6 @@
 XMLWriter: libxml2 XML Writer, comments
 --EXTENSIONS--
 xmlwriter
---SKIPIF--
-<?php
-if (!function_exists("xmlwriter_start_comment")) die("skip: libxml2 2.6.7+ required");
-?>
 --FILE--
 <?php
 

ext/xmlwriter/tests/005.phpt

@@ -2,10 +2,6 @@
 XMLWriter: libxml2 XML Writer, comments
 --EXTENSIONS--
 xmlwriter
---SKIPIF--
-<?php
-if (!function_exists("xmlwriter_start_comment")) die("skip: libxml2 2.6.7+ required");
-?>
 --FILE--
 <?php
 

ext/xmlwriter/tests/009.phpt

@@ -2,10 +2,6 @@
 XMLWriter: PI, Comment, CDATA
 --EXTENSIONS--
 xmlwriter
---SKIPIF--
-<?php
-if (!function_exists("xmlwriter_start_comment")) die("skip: libxml2 2.6.7+ required");
-?>
 --FILE--
 <?php
 /*

ext/xmlwriter/tests/OO_005.phpt

@@ -2,10 +2,6 @@
 XMLWriter: libxml2 XML Writer, comments
 --EXTENSIONS--
 xmlwriter
---SKIPIF--
-<?php
-if (!function_exists("xmlwriter_start_comment")) die("skip: libxml2 2.6.7+ required");
-?>
 --FILE--
 <?php
 

ext/zlib/tests/gzencode_variation1-win32.phpt

@@ -4,22 +4,12 @@ Test gzencode() function : variation
 zlib
 --SKIPIF--
 <?php
-
-if( substr(PHP_OS, 0, 3) != "WIN" ) {
+if (substr(PHP_OS, 0, 3) != "WIN") {
   die("skip only for Windows");
 }
-
-
 ?>
 --FILE--
 <?php
-if(!function_exists("gzdecode")) {
-    function gzdecode($data)
-    {
-       return gzinflate(substr($data,10,-8));
-    }
-}
-
 
 include(__DIR__ . '/data.inc');
 

sapi/fpm/tests/reload-uses-sigkill-as-last-measure.phpt

@@ -1,5 +1,7 @@
 --TEST--
 If SIGQUIT and SIGTERM during reloading fail, SIGKILL should be sent
+--EXTENSIONS--
+pcntl
 --SKIPIF--
 <?php
 include "skipif.inc";

tests/basic/req44164.phpt

@@ -1,10 +1,7 @@
 --TEST--
 Req #44164 (Handle "Content-Length" HTTP header when zlib.output_compression active)
---SKIPIF--
-<?php
-if (!function_exists('gzdeflate'))
-    die("skip zlib extension required");
-?>
+--EXTENSIONS--
+zlib
 --INI--
 zlib.output_compression=On
 --ENV--