DEV: Fix methods removed in Ruby 3.2 (#15459)

* File.exists? is deprecated and removed in Ruby 3.2 in favor of
File.exist?
* Dir.exists? is deprecated and removed in Ruby 3.2 in favor of
Dir.exist?

script/bench.rb

@@ -112,7 +112,7 @@ unless $? == 0
   abort "Apache Bench is not installed. Try: apt-get install apache2-utils or brew install ab"
 end
 
-unless File.exists?("config/database.yml")
+unless File.exist?("config/database.yml")
   puts "Copying database.yml.development.sample to database.yml"
   `cp config/database.yml.development-sample config/database.yml`
 end