Fix memory cleanup in tests

:Release Notes:
Some memory cleanup in tests was fixed
'check' make target has been changed to run fast

:Detailed Notes:
There were a few missed cleanup functions and memory checker had
some complaints on this.
Test with deallocated mutex was removed from the incoming transport test.
test_clock and test_timersource were excluded from the `check` target
to speed up its execution.

:Testing Performed:
Tests have been run and checked for memory leaks.

:QA Notes:

:Issues Addressed:
[GF-45291] LS2: Investigate and fix potential memory leaks

Open-webOS-DCO-1.0-Signed-off-by: Alexandr Smoktal <alexandr.smoktal@lge.com>

Change-Id: I50d21de0f18fe19c00563f26c73bda77dffae690
Reviewed-on: https://g2g.palm.com/3853
Reviewed-by: Build Verification
Reviewed-by: Alexandr Smoktal <alexandr.smoktal@lge.com>
Tested-by: Alexandr Smoktal <alexandr.smoktal@lge.com>
Reviewed-by: Keith Derrick <keith.derrick@lge.com>