This adds a file-based test framework to crypto/test. It knows how to
parse formats similar to either upstream's evp_test and our aead_test.

hmac_test has been converted to that with tests from upstream's
evp_test. Upstream tests it against the deprecated EVP_PKEY_HMAC API,
which will be tested by running evp_test against the same input file, to
avoid having to duplicate the test vectors. hmac_test runs those same
inputs against the supported HMAC_CTX APIs.

Change-Id: I9d2b6adb9be519760d1db282b9d43efd6f9adffb
Reviewed-on: https://boringssl-review.googlesource.com/4701
Reviewed-by: Adam Langley <agl@google.com>