Add some OQS tests to x509/x509_test.cc and evp/evp_test.cc

[xvzcf]

This might preempt issues such as https://github.com/open-quantum-safe/boringssl/issues/58

[claucece]

I'll start looking at this this week ;)

[baentsch]

#68 might cause a significant code base change that could throw anybody's work back, so question to @claucece : Do you have something to merge on this issue that should be merged before adding in #68?

[claucece]

@baentsch yes, I was doing intial testing. But, don't feel stopped by it. I'll rebase and fix any conflicts.