AC-1479: Incorrect qty to ship after few creditmemos

Fix unit and integration test

Author: sumesh-GL

app/code/Magento/Sales/Test/Unit/Model/Order/ItemTest.php

@@ -105,9 +105,7 @@ public function testGetOrder()
             ->willReturnSelf();
 
         // Create a mock factory for this specific test
-        $mockFactory = $this->getMockBuilder(OrderFactoryStub::class)
-            ->onlyMethods(['create'])
-            ->getMock();
+        $mockFactory = $this->createPartialMock(SalesOrderFactory::class, ['create']);
         $mockFactory->expects($this->once())
             ->method('create')
             ->willReturn($order);

dev/tests/integration/testsuite/Magento/Sales/Model/Order/ItemTest.php

@@ -124,6 +124,6 @@ public function testGetSimpleQtyToShip()
 
         // Assert getSimpleQtyToShip value
         // Qty to ship = Qty ordered (10) - Qty shipped (2) - Qty refunded (4) = 4
-        $this->assertEquals(4, $orderItem->getSimpleQtyToShip(), 'Simple qty to ship should be 3');
+        $this->assertEquals(4, $orderItem->getSimpleQtyToShip(), 'Simple qty to ship should be 4');
     }
 }