* Enable BF16 for creating global tensor and reduce_mean.

* Functional test with small model.

* Add oneDNN AXPY handler.

* Add fallback for small tensors.

* Fix ifdefs

* Remove unnecessary namespace prefixes and add missing headers.

* Guard handler_axpy with proper ifdefs.

* Compilation of this function is possible only when Paddle is not build
with CUDA nor HIP.

* Move AXPY handler code to separate files.

* Use oneDNN AXPY handler in SGD op.

* Use axpy handler only when Paddle is built with oneDNN.

* Add test for SUM BF16 with big rows.

* Fix SFINAE rules for elementwise_add_to.

* Add test case for SGD with big rows.

* update

* update
Co-authored-by: NAdam Osewski <adam.osewski@intel.com>

* Initial draft for SGD BG16 kernel.

* Unit tests for SGD with BF16 data type.

* Add VLOG message to SGD BF16 op CPU kernel.

* Enhance error messages and error types.

* Refactor SGD op kernels to leverage some common code.

* Make easier to add new kerne invoke code.

* Fix SGD op kernel for sparse grad.

* Unify quotes style.

* Fix error for ROCM compilation.

* Use specialized PADDLE_ENFORCE_xx functions.