minor symfony#25804 [XmlUtils] allow dashes in cwd pathname when running the tests (leberknecht)

This PR was submitted for the master branch but it was merged into the 3.4 branch instead (closes symfony#25804).

Discussion
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[XmlUtils] allow dashes in cwd pathname when running the tests

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Small fix the allow dashes in cwd pathname when running tests. The change was introduced with ref 7473981 so 2.x and 3.x branches should be fine.
Steps to reproduce (assuming all required libraries are installed):

    mkdir /tmp/folder-with-dashes/ && cd $_
    git clone git@github.com:symfony/symfony.git
    cd symfony && composer install --prefer-dist
    ./phpunit --stop-on-failure

Commits
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db5f8de allow dashes in cwd pathname when running the tests

Author: nicolas-grekas

src/Symfony/Component/Config/Tests/Util/XmlUtilsTest.php

@@ -55,7 +55,7 @@ public function testLoadFile()
             XmlUtils::loadFile($fixtures.'valid.xml', array($mock, 'validate'));
             $this->fail();
         } catch (\InvalidArgumentException $e) {
-            $this->assertRegExp('/The XML file "[\w:\/\\\.]+" is not valid\./', $e->getMessage());
+            $this->assertRegExp('/The XML file "[\w:\/\\\.-]+" is not valid\./', $e->getMessage());
         }
 
         $this->assertInstanceOf('DOMDocument', XmlUtils::loadFile($fixtures.'valid.xml', array($mock, 'validate')));