benchmark_json_merge.py is only used in compare-results and merge-result-jsons.py which already are Python3 compatible. Migrating to Python3 would appear to create no issues.
Pull request: https://github.com/WebKit/WebKit/pull/16770
<rdar://problem/114345624>
Committed 267216@main (1238f6638270): <https://commits.webkit.org/267216@main> Reviewed commits have been landed. Closing PR #16770 and removing active labels.