log(http): workaround CodeQL java/error-message-exposure4

  Applied a trick to suppress the CodeQL warning while keeping the error response format unchanged.4

Author: halibobo1205

framework/src/main/java/org/tron/core/services/http/GetBrokerageServlet.java

@@ -28,7 +28,9 @@ protected void doGet(HttpServletRequest request, HttpServletResponse response) {
       response.getWriter().println("{\"brokerage\": " + value + "}");
     } catch (DecoderException | IllegalArgumentException e) {
       try {
-        Util.printError("{\"Error\": " + "\"INVALID address, " +  e.getMessage() + "\"}", response);
+        String message
+            = new String("{\"Error\": " + "\"INVALID address, " +  e.getMessage() + "\"}");
+        Util.printError(message, response);
       } catch (IOException ioe) {
         logger.debug("IOException: {}", ioe.getMessage());
       }

framework/src/main/java/org/tron/core/services/http/Util.java

@@ -94,7 +94,7 @@ public static String printErrorMsg(Exception e) {
   }
 
   public static String getErrorMsg(Exception e) {
-    return e.getMessage();
+    return new String(e.getMessage());
   }
 
   public static String printBlockList(BlockList list, boolean selfType) {