Roll-forward:

Move autotuning.proto to tensorflow/core/protobuf. This is in preparation of the next patch, to tensorflow::Logger::LogProto() for TF convolutions.

This patch also has a functional change, that is to not log an AutotuneResult if the profile result is not valid. Usually they are just unsupported configurations. Ideally we'd log the exact error message of unsupported configs, but today StreamExecutor doesn't propagate it anyway.

PiperOrigin-RevId: 236760232