Remove references to i18nVariable, CommentType, CommentVariable and CommentVariablePerCommentType from the global deprecation listener list.

I see one green test, so I feel safe with RTBC.

+++ b/core/modules/comment/tests/src/Kernel/Plugin/migrate/source/d6/CommentVariablePerCommentTypeTest.php
@@ -3,20 +3,36 @@
+  use ExpectDeprecationTrait;
...
+  public function testSource(array $source_data, array $expected_data, $expected_count = NULL, array $configuration = [], $high_water = NULL) {
+    $this->expectDeprecation('CommentVariablePerCommentType is deprecated in Drupal 8.4.x and will be removed before Drupal 9.0.x. Use \Drupal\node\Plugin\migrate\source\d6\NodeType instead.');
+    $this->expectDeprecation('CommentVariable is deprecated in Drupal 8.4.x and will be removed before Drupal 9.0.x. Use \Drupal\node\Plugin\migrate\source\d6\NodeType instead.');
+    parent::testSource($source_data, $expected_data, $expected_count, $configuration, $high_water);

I feel a little nitpicky about this pattern, because the string literals are completely literal and don't need to be assembled. They maybe should be @expectedDeprecation annotations.

Other than the minor nit, LGTM.

@mikelutz thanks for working on this. It's great to see this being tackled.

I agree with @Mile23 let's not use the ExpectedDeprecationTrait unnecessarily. Also it would be good to confirm that we have matching non-legacy test coverage.

For example for i18nVariable we have both:

• \Drupal\Tests\migrate_drupal\Kernel\Plugin\migrate\source\d6\i18nVariableTest
• \Drupal\Tests\migrate_drupal\Unit\source\d6\i18nVariableTest (already a legacy test)

But for we have VariableTranslation:

• \Drupal\Tests\migrate_drupal\Unit\source\d6\VariableTranslationTest

So are we losing test coverage in any way?

@mikelutz but atm the i18Variable kernel test is a kernel test of VariableTranslation - because i18Variable extends VariableTranslation. With this change we're marking it for removal so either #3004684: Create a Kernel Test for VariableTranslation source plugin is a blocker or we need to do it here.

Changed the status on #3004684: Create a Kernel Test for VariableTranslation source plugin to outdated.

@mikelutz explained what's happening in this patch to me, since I was confused about why we are adding a completely new test here. It makes sense now. Let's do it.

Dang.

Thanks! RTBC when green.

Committed 44b86a4 and pushed to 8.7.x. Thanks!