kunit: Fix kunit.py --raw_output option

Due to the raw_output() function on kunit_parser.py actually being a
generator, it only runs if something reads the lines it returns. Since
we no-longer do that (parsing doesn't actually happen if raw_output is
enabled), it was not printing anything.

Fixes: 45ba7a89 ("kunit: kunit_tool: Separate out config/build/exec/parse")
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>