Do not write to debug.log in activerecord tests on CI

activerecord/test/support/connection.rb

@@ -21,7 +21,13 @@ def self.test_configuration_hashes
   def self.connect
     ActiveRecord.async_query_executor = :global_thread_pool
     puts "Using #{connection_name}"
-    ActiveRecord::Base.logger = ActiveSupport::Logger.new("debug.log", 1, 100 * 1024 * 1024)
+
+    if ENV["CI"]
+      ActiveRecord::Base.logger = nil
+    else
+      ActiveRecord::Base.logger = ActiveSupport::Logger.new("debug.log", 1, 100.megabytes)
+    end
+
     ActiveRecord::Base.configurations = test_configuration_hashes
     ActiveRecord::Base.establish_connection :arunit
     ARUnit2Model.establish_connection :arunit2