[internal] Use Real Trace Viewer for tracing tests

[mxschmitt]

Rewrite TestTracing.java so it uses the real trace viewer under the hood. This will align with what we do with the other language ports. PRs for inspiration:

• test: refactor trace viewer tests to use actual trace viewer playwright-python#2885
• test: refactor TracingTests to use actual Trace Viewer playwright-dotnet#3188

Also rebasing it in the future makes it much easier when they don't diverge.