runtime-test.py: Split different tests inside selftest.py
There were two completely different tests inside selftest.py,
and the only reason for them to be together was that both needed
the same mechanism to execute (run testimage from within selftest)
This fixes the design issue and error-prone situation by separating
these tests. In add a new module for dnf-runtime and also has an
extra time added to running the tests, but it is minimal since
the builds reuse data from previuous build.
[YOCTO #11436]
Signed-off-by: Humberto Ibarra <humberto.ibarra.lopez@intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
