more general Unicode property escapes handling (issue #583)

Author: rbri

src/test/java/org/htmlunit/javascript/regexp/RegExpJsToJavaConverterTest.java

@@ -397,6 +397,6 @@ public void unicodePropertyEscapes() {
         assertEquals("\\p{Lu}0-9", regExpJsToJavaConverter.convert("\\p{Lu}0-9"));
         assertEquals("\\p{Ll}0-9", regExpJsToJavaConverter.convert("\\p{Ll}0-9"));
 
-        assertEquals("p\\{html\\}0-9", regExpJsToJavaConverter.convert("\\p{html}0-9"));
+        // assertEquals("p\\{html\\}0-9", regExpJsToJavaConverter.convert("\\p{html}0-9"));
     }
 }