* [ONNX] Added function for converting negative axes.

* [ONNX] Bugfix

* [ONNX] Code formatting

* [ONNX] Changed name of function.

* Added validation for axis/axes.

* Changed abs to llabs for int64 argument.

* Changed validation function.

* [ONNX] Added function for converting negative axes.

* [ONNX] Bugfix

* [ONNX] Code formatting

* [ONNX] Changed name of function.

* Added validation for axis/axes.

* Changed abs to llabs for int64 argument.

* Changed validation function.

* Changed validation function.

* Changed validation function

* Changed rank size in onehot

* Apply suggestions from code review
Co-Authored-By: Tomasz Socha <tomasz.socha@intel.com>

* Code refactoring.

* Update flatten.cpp