Issue #3157954 by alexpott, andypost: Remove unnecessary route rebuild from tests

...dules/aggregator/tests/src/Kernel/AggregatorTitleTest.php

core/modules/block/tests/src/Functional/BlockInstallTest.php

core/modules/block/tests/src/Functional/BlockTest.php

...ock_content/tests/src/Functional/BlockContentTypeTest.php

...odules/comment/tests/src/Functional/CommentFieldsTest.php

...tests/src/Kernel/CommentDefaultFormatterCacheTagsTest.php

...omment/tests/src/Kernel/Migrate/d6/MigrateCommentTest.php

...tests/src/Functional/ContentTranslationOperationsTest.php

...ation/tests/src/Functional/ContentTranslationTestBase.php

...modules/editor/tests/src/Kernel/EditorImageDialogTest.php

...rence/EntityReferenceFieldTranslatedReferenceViewTest.php

...c/Kernel/EntityReference/EntityReferenceFormatterTest.php

core/modules/field/tests/src/Kernel/FieldAttachOtherTest.php

.../field/tests/src/Kernel/String/RawStringFormatterTest.php

...les/field/tests/src/Kernel/String/StringFormatterTest.php

...dules/field/tests/src/Kernel/String/UuidFormatterTest.php

...les/filter/tests/src/Kernel/TextFormatElementFormTest.php

core/modules/hal/tests/src/Kernel/HalLinkManagerTest.php

core/modules/hal/tests/src/Kernel/NormalizeTest.php

core/modules/hal/tests/src/Kernel/NormalizerTestBase.php