Adapt tests for libxml2 >= 2.13.0

libxml2 2.13.0 introduced some relevant changes regarding the treatment
of file paths on Windows[1].  Thus we un-xfail bug69753.phpt and its
companion, and we adjust dom004.phpt.

[1] <https://gitlab.gnome.org/GNOME/libxml2/-/commit/8ab1b122c47bfced2b59f52351507ebc1eb50218>

Author: cmb69

ext/dom/tests/dom004.phpt

@@ -9,7 +9,7 @@ in_array('compress.zlib', stream_get_wrappers()) or die('skip compress.zlib wrap
 --FILE--
 <?php
 $dom = new domdocument;
-$dom->load("compress.zlib://".__DIR__."/book.xml.gz");
+$dom->load("compress.zlib://" . str_replace("\\", "/", __DIR__) . "/book.xml.gz");
 print $dom->saveXML();
 ?>
 --EXPECT--

ext/libxml/tests/bug69753-mb.phpt

@@ -1,12 +1,11 @@
 --TEST--
 Bug #69753 - libXMLError::file contains invalid URI
---XFAIL--
-Awaiting upstream fix: https://gitlab.gnome.org/GNOME/libxml2/-/issues/611
 --EXTENSIONS--
 dom
 --SKIPIF--
 <?php
 if (substr(PHP_OS, 0, 3) != 'WIN') die("skip this test is for Windows platforms only");
+if (version_compare(LIBXML_DOTTED_VERSION, "2.13.0") < 0) die("skip fails for libxml2 < 2.13.0; https://gitlab.gnome.org/GNOME/libxml2/-/issues/611");
 ?>
 --FILE--
 <?php
@@ -17,4 +16,4 @@ $error = libxml_get_last_error();
 var_dump($error->file);
 ?>
 --EXPECTF--
-string(%d) "file:///%s/ext/libxml/tests/bug69753.xml"
+string(%d) "%s\ext\libxml\tests\bug69753私はガラスを食べられます.xml"

ext/libxml/tests/bug69753.phpt

@@ -1,12 +1,11 @@
 --TEST--
 Bug #69753 - libXMLError::file contains invalid URI
---XFAIL--
-Awaiting upstream fix: https://gitlab.gnome.org/GNOME/libxml2/-/issues/611
 --EXTENSIONS--
 dom
 --SKIPIF--
 <?php
 if (substr(PHP_OS, 0, 3) != 'WIN') die("skip this test is for Windows platforms only");
+if (version_compare(LIBXML_DOTTED_VERSION, "2.13.0") < 0) die("skip fails for libxml2 < 2.13.0; https://gitlab.gnome.org/GNOME/libxml2/-/issues/611");
 ?>
 --FILE--
 <?php
@@ -17,4 +16,4 @@ $error = libxml_get_last_error();
 var_dump($error->file);
 ?>
 --EXPECTF--
-string(%d) "file:///%s/ext/libxml/tests/bug69753.xml"
+string(%d) "%s\ext\libxml\tests\bug69753.xml"