kunit: Fix result propagation for parameterised tests

When one parameter of a parameterised test failed, its failure would be
propagated to the overall test, but not to the suite result (unless it
was the last parameter).

This is because test_case->success was being reset to the test->success
result after each parameter was used, so a failing test's result would
be overwritten by a non-failing result. The overall test result was
handled in a third variable, test_result, but this was discarded after
the status line was printed.

Instead, just propagate the result after each parameter run.

Signed-off-by: David Gow <davidgow@google.com>
Fixes: fadb08e7 ("kunit: Support for Parameterized Testing")
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>