Verify op_ is not a nullptr

If op_ is a nullptr, the test runner can SIGSEGV.

Test: manual, atest EncryptionOperationsTest#TripleDesCbcPkcs7PaddingCorrupted
Bug: None

Signed-off-by: Brian J Murray <brianjmurray@google.com>
Change-Id: Ibdd6139952ca8bc83ac1a82202839feee39562e1
1 file changed