* add fp16 and bf16 support for instance_norm

* fix /= operator which not support bf16

* fix instance_norm_grad kernel and unittests.

* fix fp32 unittests.

* fix instance_norm_kernel and unittests.

* fix instance_norm_grad_kernel and unittest threshold.

* add fp16/bf16 for instance_norm_grad_grad op.

* add bf16 dtype check.

* fix conflicts.

* fix cpu support for fp32 op and fix type in instance_norm_grad_kernel.

* fix type in instance_norm_kernel.

* fix bf16 outputs in unittests and refine codes.

* fix dx computation.

* delete unuseful params and head including.

* add fp16/bf16 for static graph.

* fix device condiction for instance_norm op.

* fix instance_norm_grad_grad and bf16 op tests.

* fix op_test to support grad of bf16 can be compared with fp32.

* remove updates.

* add self-defined grad.