Fix Request.clone

[ronag]

node-fetch tests fail and are therefore disabled

[ronag]

@szmarczak would you like to have a go at this one?

[szmarczak]

Sure, I'll do this after 2h. Working atm.

[szmarczak]

nodejs/node#39758

[ronag]

@szmarczak Fixed Response.clone now we just need to sort Request.clone.