The daughter of the once-oldest president‚ Ronald Reagan‚ who was 77 when he took office‚ thinks cognitive tests for presidential candidates would be “a good idea‚” she said in an interview that aired Sunday. “Just what we know about what age can do‚ it doesn’t always do that‚ but it would probably be a good idea‚” Patti Davis said on NBC’s Meet the Press‚ in response to a question from host Kristen Welker about whether she agreed with the prospect.  Reagan was elected in 1980‚ when...