Exclude failing sub-tests in Wycheproof job 

We need to figure out the way to exclude failing wycheproof tests from the build job. [Wycheproof documentation](https://github.com/google/wycheproof), [Bazel manual](https://docs.bazel.build/versions/master/user-manual.html) does not seem to document a simple way. Need to investigate. 