Simplify trim() function

src/main/java/com/schibsted/spt/data/jslt/impl/BuiltinFunctions.java

@@ -828,40 +828,7 @@ public JsonNode call(JsonNode input, JsonNode[] arguments) {
       if (string == null)
         return NullNode.instance;
 
-      int prefix = 0; // first non-space character
-
-      // first: find leading spaces
-      for (;
-           prefix < string.length() && isSpace(string, prefix);
-           prefix++)
-        ;
-
-      // if the whole thing is spaces we're done
-      if (prefix == string.length())
-        return new TextNode("");
-
-      int suffix = string.length() - 1; // last non-space character
-
-      // second: find trailing spaces
-      for (;
-           suffix >= 0 && isSpace(string, suffix);
-           suffix--)
-        ;
-
-      // INV suffix >= prefix (they're equal if non-space part is 1 character)
-
-      // if there are no leading or trailing spaces: keep input
-      if (prefix == 0 && suffix == string.length() - 1 &&
-          arguments[0].isTextual())
-        return arguments[0];
-
-      // copy out middle section and we're done
-      return new TextNode(string.substring(prefix, suffix + 1));
-    }
-
-    private static boolean isSpace(String string, int ix) {
-      char ch = string.charAt(ix);
-      return ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n';
+      return new TextNode(string.trim());
     }
   }