Multiple Identical ExperimentalWarnings

[LJNeon]

• Version: v13.9.0
• Platform: Ubuntu 18.04
• Subsystem: N/A

What is the expected behavior?

Experimental warnings will only be logged once.

What do you see instead?

The same warning is logged multiple times to console.

[LJNeon]

The third warning is logged by process.on("warning"), but the experimental ESM module loader warning isn't emitting that event so I presume it's unintentional as well.

[jasnell]

It definitely should only be output to the console once. The process.on('warning') is working as expected. The warning is emitted using process.emitWarning(), which always forwards all warnings to process.on('warning') in addition to the default behavior of printing to the console.

[aduh95]

These warnings are meant to go away (#31845), if this is issue is specific to this very warning, it's probably not worth spending time investigate it.

[juanarbol]

As long as #31845 is landed now, I think this issue could be closed.