runner: Add explicit "notrun" results for tests that were not executed

When possible, all tests we know we were going to attempt to execute
now appear in the results as "notrun". The only known case where it's
not possible to add an explicit "notrun" is when running in
multiple-mode, because "no subtests" and "run all subtests, we didn't
list them beforehand" are represented the same.

v2: Rebase and adjust to already landed json changes

Signed-off-by: Petri Latvala <petri.latvala@intel.com>
Cc: Martin Peres <martin.peres@linux.intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Acked-by: Martin Peres <martin.peres@linux.intel.com>
Reviewed-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>