tests: use 'FIXME' instead of 'fail' for expected failures

Seeing 'fail' in the test reports and the explanation that it means
"Test failed, but it was an expected failure" somewhat gives the
impression that these failures are ok. Actually these failures represent
known bugs/issues that we haven't yet fixed but we don't want them to
result in 'make check' ailing. To try and better reflect the severity of
these issues we now report them as 'FIXME'.

Reviewed-by: Neil Roberts <neil@linux.intel.com>