Fix Functional Test Magento\Sales\Test\TestCase\CreateCreditMemoEntityTest::test with data set "CreateCreditMemoEntityTestVariation1_0"

[smoskaluk]

Preconditions

1. Magento with MSI 'Single Stock' mode

Steps to reproduce

1. Run Test Magento\Sales\Test\TestCase\CreateCreditMemoEntityTest::test with data set "CreateCreditMemoEntityTestVariation1_0"

Expected result

1. Test should pass successfully.

Actual result

1. Test fails.
   Form data not equals to passed from fixture:
   quantity_and_stock_status:
   • qty: "777" instead of "776"
     Failed asserting that false is true.

/var/www/html/dev/tests/functional/tests/app/Magento/Catalog/Test/Constraint/AssertProductForm.php:72
/var/www/html/dev/tests/functional/tests/app/Magento/Sales/Test/Constraint/AssertProductQtyDecreasedAfterCreditmemo.php:71
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/ObjectManager/Factory.php:57
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/ObjectManager.php:81
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/Constraint/AbstractConstraint.php:155
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/Constraint/Composite.php:109
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/TestCase/Injectable.php:231
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/TestCase/Functional.php:300
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/TestCase/Functional.php:217
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/TestCase/Injectable.php:210
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/TestCase/Scenario.php:81
/var/www/html/dev/tests/functional/vendor/magento/mtf/Magento/Mtf/TestCase/Injectable.php:166

Notice:

Creating Credit Memo with 'return to stock' not affecting field "Quantity", as well as creating Order - all changes applying to 'salable quantity' of the product with help of reservations and compensational reservations in DB