kunit: Reset suite count after running tests

kunit: Reset suite count after running tests

There are some KUnit tests (KFENCE, Thunderbolt) which, for various
reasons, do not use the kunit_test_suite() macro and end up running
before the KUnit executor runs its tests. This means that their results
are printed separately, and they aren't included in the suite count used
by the executor.

This causes the executor output to be invalid TAP, however, as the suite
numbers used are no-longer 1-based, and don't match the test plan.
kunit_tool, therefore, prints a large number of warnings.

While it'd be nice to fix the tests to run in the executor, in the
meantime, reset the suite counter to 1 in __kunit_test_suites_exit.
Not only does this fix the executor, it means that if there are multiple
calls to __kunit_test_suites_init() across different tests, they'll each
get their own numbering.

kunit_tool likes this better: even if it's lacking the results for those
tests which don't use the executor (due to the lack of TAP header), the
output for the other tests is valid.

Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>