Revert "XFAIL tests (GH-8588)"

This reverts commit f2ac4f2.

Author: arnaud-lb

ext/opcache/tests/bug78175_2.phpt

@@ -11,8 +11,6 @@ opcache
 <?php
 if (PHP_OS_FAMILY == 'Windows') die('skip Preloading is not supported on Windows');
 ?>
---XFAIL--
-GH-8588
 --FILE--
 <?php
 var_dump(get_class(Loader::getLoader()));

ext/opcache/tests/bug78376.phpt

@@ -11,8 +11,6 @@ opcache
 <?php
 if (PHP_OS_FAMILY == 'Windows') die('skip Preloading is not supported on Windows');
 ?>
---XFAIL--
-GH-8588
 --FILE--
 <?php
 const CNST = 'bbbb';

ext/opcache/tests/preload_method_static_vars.phpt

@@ -11,8 +11,6 @@ opcache
 <?php
 if (PHP_OS_FAMILY == 'Windows') die('skip Preloading is not supported on Windows');
 ?>
---XFAIL--
-GH-8588
 --FILE--
 <?php
 Foo::test();

ext/opcache/tests/preload_trait_static.phpt

@@ -11,8 +11,6 @@ opcache
 <?php
 if (PHP_OS_FAMILY == 'Windows') die('skip Preloading is not supported on Windows');
 ?>
---XFAIL--
-GH-8588
 --FILE--
 <?php
 $bar = new Bar;