ktest: Put back in the CONFIG_BISECT_CHECK

The new rewrite left out the CONFIG_BISECT_CHECK, which allows the
user to test that their "bad" config still is bad and their "good"
config still is good. This is especially important as the configs
are passed through a "make oldconfig" to update them with the lastest
kernel. Things could change that causes a bad config to work, or a
good config to break. The check is done after the configs have run
through the oldconfig processing.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>