Run config unit tests from scons

Currently they have been added to flaky-tests and will be promoted
once we have it run successfully consistently. The workflow is to have
 * scons controller/src/api-lib
 * scons controller/src/config/api-server
 * scons controller/src/config/schema-transformer
run the unit tests. A future commit will try to have this run from
within source using ./run_tests.sh
Also add explicit list of tests in common as test_utils/test_common are helpers instead of tests

Change-Id: I5b72c6a18e8be9bcdf6d68146b9c220a9196746e
Merge "Run config unit tests from scons"