implement some existed operators for TF

[Co1lin]

• implement some existed operators for TF
• fix the GPU device name for TF (if we directly use GPU device name got by list_physical_devices in TF, we will encounter an exception when using this device via with: ValueError: Unknown attribute 'physical_device' is encountered while parsing the device spec: '/physical_device:GPU:0'.)

[ganler]

Thanks for the contribution! Just need to confirm with the review comments. Meanwhile, please confirm that dispatchable operators can at least work with one backend, thanks!