Remove testing the internals of DependencySerializationTrait from LocaleTranslationTest

Problem/Motivation

Followup to [#3128389#31]

Copied from the entire comment here.

+++ b/core/modules/locale/tests/src/Kernel/LocaleTranslationTest.php
@@ -0,0 +1,48 @@
+    // Ensure that all properties on the unserialized object match the original.
+    $translation_reflection = new \ReflectionObject($translation);
+    $unserialized_reflection = new \ReflectionObject($unserialized);
+    // Ignore the '_serviceIds' property in the comparison.
+    $properties = array_filter($translation_reflection->getProperties(), function ($value) {
+      return $value->getName() !== '_serviceIds';
+    });
+    foreach ($properties as $value) {
+      $value->setAccessible(TRUE);
+      $unserialized_property = $unserialized_reflection->getProperty($value->getName());
+      $unserialized_property->setAccessible(TRUE);
+      $this->assertEquals($unserialized_property->getValue($unserialized), $value->getValue($translation));
+    }

This should be removed from the test. It's testing the internals of DependencySerializationTrait that are tested elsewhere. Adding things like this here makes it harder to change the internals. For example - this test unnecessarily impacts #2531564: Fix leaky and brittle container serialization solution

Can we get a follow-up to remove this from 9.1.x and 9.0.x?

Steps to reproduce

Proposed resolution

Remove the indicated code

Remaining tasks

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User interface changes

API changes

Data model changes

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