[CodeCovarage] Automatic tests for DPL test framework

[CodeCovarage] Automatic tests for DPL test framework

[Issue#]       LINUXWRT-664
[Feature]      Tests/tests fix
[Cause]        Those tests are returning actual result of tests. Returned result should be catch and compared with expected. That comparsion should give pass or fail.
[Solution]     Add macro for catching tests results to make tests automatic.
[Verification] Build "WITH_TESTS ON" and "WITH_CHILD ON". Run:
   wrt-commons-tests-test-runner-child --output=text --regexp='t0'
   wrt-commons-tests-test-runner-child --output=text --regexp='t1'
All should pass (binary may have name wrt-commons-tests-test if previous do not exist).

Change-Id: Ie7b008813b666ceb75de28119286e497d1c4b7ac