Remove unnecessary methods. (#134)

* Remove unnecessary methods.

src/Schema.php

@@ -675,20 +675,4 @@ protected function normalizeRowKeyCase(array $row, bool $multiple): array
 
         return array_change_key_case($row, CASE_LOWER);
     }
-
-    /**
-     * @return bool whether this DBMS supports [savepoint](http://en.wikipedia.org/wiki/Savepoint).
-     */
-    public function supportsSavepoint(): bool
-    {
-        return $this->db->isSavepointEnabled();
-    }
-
-    /**
-     * @inheritDoc
-     */
-    public function getLastInsertID(?string $sequenceName = null): string
-    {
-        return $this->db->getLastInsertID($sequenceName);
-    }
 }