Problem/Motivation comment_entity_storage_load() attempts to optimize away a database query each time entities are loaded that don't have comment fields attached. Unfortunately when caches are cold - such as after submitting the modules page, the field check takes 125ms and 4mb of memory. Proposed resolution Query statistics just-in-time and in bulk to avoid needing the loading etc and the field checks. Remaining tasks

For example  
Drupal\Core\Entity\Entity::id() returns $this->id(or NULL),
Drupal\Core\Entity\ContentEntityBase::id() returns $this->id->value,
Drupal\Core\Entity\ContentEntityBase::uuid() returns $...