Merge pull request #19881 from sikachu/silence-mysql-errno-warning

Silence warning from MySQL::Error object in test

activerecord/test/cases/disconnected_test.rb

@@ -21,7 +21,9 @@ def setup
       @connection.execute "SELECT count(*) from products"
       @connection.disconnect!
       assert_raises(ActiveRecord::StatementInvalid) do
-        @connection.execute "SELECT count(*) from products"
+        silence_warnings do
+          @connection.execute "SELECT count(*) from products"
+        end
       end
     end
   end