patchtest: log errors and failures at end

patchtest: log errors and failures at end

At the moment, running patchtest locally will only print failures and errors
to the log when the not passing test case is executed. This might lead to
people overlooking issues with their patches, so print a log line at the
end if testcases showed issues. This should make it more easy to spot then
before.

Fixes [YOCTO #15389]

Signed-off-by: Simone Weiß <simone.p.weiss@posteo.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>