SOLR-16898: Remove a println statement from JSONTestUtil

[patsonluk]

https://issues.apache.org/jira/browse/SOLR-16898

Description

It's found that a possibly debug statement e5ca599#diff-1098b7bd3712859836c1915cc5af5190782fb27183e5750d4bbf1d2d3e229c92R80 creates a large amount of log for our test case in https://github.com/cowpaths/fullstory-solr/actions/runs/5591120540/jobs/10221763319 and caused GC limit exception hence test failure

Solution

We should remove such println assuming that's leftover from debugging

Tests

No new tests

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide

[risdenk]

If it's needed could even leave it as a debug log using the logger, we should not be using println in general