Fix fetchAll(obj) only getting one record.

Refs #12230

src/Database/Statement/PDOStatement.php

@@ -126,7 +126,7 @@ class PDOStatement extends StatementDecorator
             return $this->_statement->fetchAll(PDO::FETCH_ASSOC);
         }
         if ($type === static::FETCH_TYPE_OBJ) {
-            return $this->_statement->fetch(PDO::FETCH_OBJ);
+            return $this->_statement->fetchAll(PDO::FETCH_OBJ);
         }
 
         return $this->_statement->fetchAll($type);

tests/TestCase/Database/QueryTest.php

@@ -3660,7 +3660,7 @@ class QueryTest extends TestCase
         $result = $query
             ->select(['d' => $query->func()->now('date')])
             ->execute();
-        $this->assertEquals([['d' => date('Y-m-d')]], $result->fetchAll('assoc'));
+        $this->assertEquals([(object)['d' => date('Y-m-d')]], $result->fetchAll('obj'));
 
         $query = new Query($this->connection);
         $result = $query