Prevent test failures caused by encoding issues

Temporarily use UTF-8 to parse stylesheets instead of system encoding until encoding detection is implemented. Use ASCII characters in resource file names

DEVSIX-1446

Author: Snipx

src/main/java/com/itextpdf/html2pdf/css/parse/CssStyleSheetParser.java

@@ -117,7 +117,7 @@ public static CssStyleSheet parse(InputStream stream, String baseUrl) throws IOE
         }
 
         CssParserStateController controller = new CssParserStateController(baseUrl);
-        Reader br = PortUtil.wrapInBufferedReader(new InputStreamReader(stream)); // TODO define charset
+        Reader br = PortUtil.wrapInBufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8)); // TODO determine charset correctly DEVSIX-1458
         char[] buffer = new char[8192];
         int length;
         while ((length = br.read(buffer, 0, buffer.length)) > 0) {