Re-add missing test to kernel.pro

Patch 9a08483d763dacfca6029f7a8970846e83df0e2a introduced a regression,
tst_qmetatype test was not meant to be removed.

Change-Id: I5456ffbbd9d9f8e461f828c6183e46dabf67952b
Reviewed-by: Sergio Ahumada <sahumada@blackberry.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>