The encryptBlock and decryptBlock functions are already tested
(via the public API) by TestCipherEncrypt and TestCipherDecrypt
respectively. Both sets of tests check the output of the two
functions against the same set of FIPS 197 examples. I therefore
think it is safe to delete these two tests without losing any
coverage.

Deleting these two tests will make it easier to modify the
internal API, which I am hoping to do in future CLs.

Change-Id: I0dd568bc19f47b70ab09699b507833e527d39ba7
Reviewed-on: https://go-review.googlesource.com/22115Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>