test_xml_output: add tests for valid duration for tests
test_xml_output: add tests for valid duration for tests

This is to check for the case where the duration is not -1
or in [0, CK_DEFAULT_TIMEOUT]. There was an issue with NO_FORK
mode where the duration was not valid.

git-svn-id: d023f1085a36f7a677188d00334e37d38ffecf51@927 64e312b2-a51f-0410-8e61-82d0ca0eb02a

brarcher/check,krichter722/check,libcheck/check,9fcc/check,libcheck/check,libcheck/check,libcheck/check,libcheck/check,krichter722/check,brarcher/check,9fcc/check,brarcher/check,krichter722/check,brarcher/check,krichter722/check,9fcc/check,brarcher/check,krichter722/check,9fcc/check,9fcc/check