Add Firefox data for FileList API (#7495)
Add Firefox data for FileList API (#7495)

This commit updates the Firefox data for the FileList API based upon
results from the mdn-bcd-collector project, along with a little bit of
mirroring to Firefox Android.
chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data