Some standards fixes in entity_test.module and EntityApiTest.php, motivated by "DatabaseStorageController can't catch exceptions"

Follow up for #1634442: DatabaseStorageController can't catch exceptions

Problem/Motivation

Non-blocking standards fixes from 1634442:

+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityApiTest.phpundefined
@@ -90,4 +91,52 @@ protected function assertCRUD($entity_type, User $user1) {
+    * Tests that exceptions are properly thrown when saving or deleting an
+    * entity.

function docs blocks should be one line < 80 chars.

+++ b/core/modules/system/tests/modules/entity_test/entity_test.moduleundefined
@@ -379,3 +379,21 @@ function entity_test_entity_form_display_alter(EntityFormDisplay $form_display,
+ * Implements hook_entity_presave()
...
+ * Implements hook_entity_predelete()

these should be sentences (end with a period)

https://drupal.org/node/1354#functions

All summaries (first lines of docblocks) must be under 80 characters, start with a capital letter, and end with a period (.). They must provide a brief description of what a function does, what a class does, what a file contains, etc.

Proposed resolution

fix those, and any thing else from entity_test.module,
like

• (done) removed in #2134857: PHPUnit test the entity base classes "type casting in function entity_test_label_callback($entity_type, $entity, $langcode = NULL) {
  and in the doc block for that function"
• ?

Remaining tasks

Initial patch.

User interface changes

No.

API changes

No.