I don't think this quite qualifies as proof the jank is caused by GC. Could you try taking a performance profile over the time that causes jank? Press F12 to open dev tools in NW.js, and then start a recording in the Performance tab and try to capture the jank. If the performance profile measures the jank and actually tags the time period spent as some kind of GC, that would prove it. Until then, best not to jump to conclusions! I tried this myself but couldn't see any issue (over 30 seconds it spent <10ms in GC), but I do have a lot of memory on this system. I also tried pressing the "collect garbage" button in dev tools while the performance profile was recording, and again no significant GC time was measured.
Even if it is GC, I think it would be better to file a Chrome bug to optimise this aspect of the GC. It looks like it only needs to unload 5 tracks, and freeing memory should essentially be a matter of tagging some memory regions as free instead of in use, i.e. very little work. So I'm not sure what it could be doing that would take any noticable amount of time. If there is a problem and it gets fixed, then it also improves all games everywhere else the Chromium engine is used, e.g. in the Chrome browser, all Cordova games on Android, etc. So this would improve all platforms, which is a much better end result, rather than providing a hack to work around a GC performance issue in just one variant of the Chromium engine.