Convert evp_test to GTest.

This is a fairly shallow conversion because of the somewhat screwy Error
lines in the test which may target random functions like
EVP_PKEY_CTX_set_signature_md. We probably should revise this, perhaps
moving those to normal tests and leaving error codes to the core
operation itself.

BUG=129

Change-Id: I27dcc945058911b2de40cd48466d4e0366813a12
Reviewed-on: https://boringssl-review.googlesource.com/16988
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/sources.cmake b/sources.cmake
index f795c51..3947c93 100644
--- a/sources.cmake
+++ b/sources.cmake
@@ -38,6 +38,7 @@
   crypto/cipher_extra/test/nist_cavp/tdes_ecb.txt
   crypto/curve25519/ed25519_tests.txt
   crypto/ecdh/ecdh_tests.txt
+  crypto/evp/evp_tests.txt
   crypto/fipsmodule/aes/aes_tests.txt
   crypto/fipsmodule/bn/bn_tests.txt
   crypto/fipsmodule/ecdsa/ecdsa_sign_tests.txt