Dist/Tizen: show unit test result summary

Dist/Tizen: show unit test result summary

Aggregate all gtest and SSAT results at the end of testing.

After this, unittest-enabled gbs will show results like:

```
[  117s] GTest (total 232 cases)
[  117s]   Passed: 232 / Failed: 0 / Ignored: 0
[  117s] SSAT (total 513 cases)
[  117s]   Passed: 497 / Failed: 0 / Ignored: 16
[  117s] Grand Total: 745 cases
[  117s]   Passed: 729 / Failed: 0 / Ignored: 16
```

Changes in V2:
- made sure to call close for opened f
- use os.path.splitext
Chnaged in V3:
- with makes exceptions with fail. Handle them.

Suggested TODO in later PRs:
- Count negative test cases.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>