selftests/sgx: Add EXPECT_EEXIT() macro

Add EXPECT_EEXIT() macro, which will conditionally print the exception
information, in addition to

  EXPECT_EQ(self->run.function, EEXIT);

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>