[TASK] Execute only Unit tests in UnitTests.xml

Functional tests are not executed in this suite.

Change-Id: Iac470a2bf1196e9dc593cab4351495d541467a88
Related: #39965
Related: #39964
Reviewed-on: http://review.typo3.org/13927
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn