oeqa/core/runner: refactor for OEQA to write json testresult
Refactor the original _getDetailsNotPassed method to return
testresult details (test status and log), which will be reused
by future OEQA code to write json testresult.
Take the opportunity to consolidate and simplify the logic used
to gather test status and log within the TestResult instance.
Signed-off-by: Yeoh Ee Peng <ee.peng.yeoh@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
