Disable buchets detection code, as we are not using it for now (bug 1003266)

https://bugzilla.mozilla.org/show_bug.cgi?id=1003266
I thought it was deactivated because the feature detection didn't work for a few APIs, was throwing false negatives or negatives, so it was better to disable it completely.

I see [bug 1003266](https://bugzilla.mozilla.org/show_bug.cgi?id=1003266), but can you show me timestamps to show how slow it actually is? it'd be nice to see `window.performance` timings up in here.