OpenAL updateSourceSpace performance issue

Hi.

I'm using emscripten 3.0.1 to compile my game and I use the OpenAL implementation for audio.

I update a bunch of sources and the listener every frame and I noticed that the performance of my game would drastically decrease over time. I tracked down the issue using Google Chrome's profiler and noticed that it was coming from the [updateSourceSpace](https://github.com/emscripten-core/emscripten/blob/8e1e305519e1027726a48861a1fec5662f7e18a2/src/library_openal.js#L508).

I went a little further analyzing the issue and realized that it was more precisely coming from the updating of the panner's property ([here](https://github.com/emscripten-core/emscripten/blob/8e1e305519e1027726a48861a1fec5662f7e18a2/src/library_openal.js#L612) for instance). I edited the library_openal.js to comment out those lines and I noticed no performance issue. I also compiled using OPENAL_DEBUG, no warning or errors.

In addition, I made sure that the problem wasn't coming from a ridiculous amount of audio sources, it's not the case, I have a bunch of sources and this number does not increase.

I'd be glad to look into it further but I'm kind of stuck at this point. Does this issue ring a bell to anyone? could someone point me in a direction so I can keep investigating?

EDIT: Something else I noticed, it's a bit hard to put into words: it seems that when my simulation performance starts deteriorating, playing sounds will make it go back up like it cleared some hanging state or something...

Thank you very much!

Nathan.