Wow, that is weird. I have an old pair and a new Nokia-branded pair in cyan to match my N9. Both pairs work on N9 with the adaptor, but the old pair can be made to work just as headphones by holding/taping down the mic button (makes sense electrically). Letting go of the button after the N9 has detected headphones muffles/filters the audio.
The new pair though can't be tricked, and are noisy, as you have in your test. Which is weird and implies some additional electronics is going on inside the mic/button widget.
Anyway, hopefully they "just work" on Jolla. I'll report back.