Part of #5777. These transients are required and cannot be predicted.
If not using an external cache system, the DB is cleared still to keep
size down after invalidation.
For these 2 transients, invalidation occurs when visibility altering
product attributes are edited.
- Removed post type classes. Since they were always loaded, there was
no benefit having them split up. Combined meaning less hooked in
methods.
- Stopped loading some function files and sessions in the admin area.
They are not needed there.
- Made a few admin page classes static as they are stateless