Fix foreign key columns order in Oracle

The order of columns in foreign key constraints is not synchronized by the Oracle platform.

**Failing test:**
```bash
Doctrine\Tests\DBAL\Functional\Schema\OracleSchemaManagerTest::testListForeignKeysComposite
Failed asserting that two arrays are equal.
--- Expected
+++ Actual
@@ @@
 Array (
-    0 => 'id'
-    1 => 'foreign_key_test'
+    0 => 'foreign_key_test'
+    1 => 'id'
 )

/home/deeky/dev/doctrine/dbal/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php:672
```