Revert "Fix SchemaValidator with abstract child class in discriminator map (#9096)" (#9262)

This reverts commit bbb68d0.

Author: olsavmic

lib/Doctrine/ORM/Tools/SchemaValidator.php

@@ -239,7 +239,7 @@ public function validateClass(ClassMetadataInfo $class)
             }
         }
 
-        if (! $class->isInheritanceTypeNone() && ! $class->isRootEntity() && ! $class->reflClass->isAbstract() && ! $class->isMappedSuperclass && array_search($class->name, $class->discriminatorMap, true) === false) {
+        if (! $class->isInheritanceTypeNone() && ! $class->isRootEntity() && ! $class->isMappedSuperclass && array_search($class->name, $class->discriminatorMap, true) === false) {
             $ce[] = "Entity class '" . $class->name . "' is part of inheritance hierarchy, but is " .
                 "not mapped in the root entity '" . $class->rootEntityName . "' discriminator map. " .
                 'All subclasses must be listed in the discriminator map.';

tests/Doctrine/Tests/ORM/Tools/SchemaValidatorTest.php

@@ -225,17 +225,6 @@ public function testMappedSuperclassNotPresentInDiscriminator(): void
 
         $this->assertEquals([], $ce);
     }
-
-    /**
-     * @group 9095
-     */
-    public function testAbstractChildClassNotPresentInDiscriminator(): void
-    {
-        $class1 = $this->em->getClassMetadata(Issue9095AbstractChild::class);
-        $ce     = $this->validator->validateClass($class1);
-
-        $this->assertEquals([], $ce);
-    }
 }
 
 /**
@@ -267,35 +256,6 @@ class ChildEntity extends MappedSuperclassEntity
 {
 }
 
-/**
- * @Entity
- * @InheritanceType("SINGLE_TABLE")
- * @DiscriminatorMap({"child" = Issue9095Child::class})
- */
-abstract class Issue9095Parent
-{
-    /**
-     * @var mixed
-     * @Id
-     * @Column
-     */
-    protected $key;
-}
-
-/**
- * @Entity
- */
-abstract class Issue9095AbstractChild extends Issue9095Parent
-{
-}
-
-/**
- * @Entity
- */
-class Issue9095Child extends Issue9095AbstractChild
-{
-}
-
 /**
  * @Entity
  */