This is the only test amongst the tests for core crypto functionality
that depends on crypto/bio. This change removes that dependency. This
also factors out the duplicative hexdump logic into a shared function.
Change-Id: Ic280a71d086555a6993c05f183b94e1d38b60932
Reviewed-on: https://boringssl-review.googlesource.com/5622
Reviewed-by: Adam Langley <agl@google.com>
