Update AudioContext() data (#6801)
Update AudioContext() data (#6801)

This commit fixes the data for the AudioContext constructor thanks to
the mdn-bcd-collector project, including fixing the Chrome version and
copying the note to all Chrome-based browsers.  This also includes
prefix data suggested in https://github.com/mdn/browser-compat-data/pull/6789.

Test used: http://mdn-bcd-collector.appspot.com/tests/api/AudioContext/AudioContext
chrisdavidmills/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data