Slowness being somewhat subjective but determined by running the
test suite a few times and picking off everything that consistently
clocks in at 2 seconds or more.
Honorable mention for simple/test-tls-server-large-request, it often
runs for 10 (!) seconds or more.
Don't assume that the libcrypto and libssl that we're linked against is the same
version as the openssl command line tool. This is important because the tool has
a bug in all pre-1.0.0 versions that makes it unusable for these tests.
This test is broken for people who don't have OpenSSL 1.0.0 - but it's just
a bug in OpenSSL. Add this timeout so that it doesn't take super long to run
the tests.