Simplify mirroring code around flattening statements (#17050)
Simplify mirroring code around flattening statements (#17050)

In the recursive call to bumpSupport, the result can only be a
SimpleSupportStatement. This allows simplifying flattenStatements and it
won't actually do any flattening. Instead inline the little that remains
into bumpSupport.

This does not result in any changes to build/data.json.

Co-authored-by: Queen Vinyl Da.i'gyu-Kazotetsu <fa3c3b2c35dab953db0f41b36615b5269c1e82df@gmail.com>
mdn/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data