Added a missing guard that is breaking the build

Adjust PlaidML test tolerances

* Add LpNormalization operator along with unit tests.

* Add validation macro based on NGRAPH_CHECK.

* Add InstanceNormalization operation along with unit tests.

* Update supported ops table.

* Fix merge error.

* add send recv file

* update CMakeLists

* add to op_tbl, add to serializer

* fix bug in serializer, add MPI send recv

* not supported in MlSL

* GPU not support send recv

* add reference implementation

* send recv not supported by intel gpu

* resolve Scott's comment about construction

* style

* add comments, add to gpu not supported list

* using Output<Node> instead of shared_ptr<Node>

* add test

* disable test for MLSL

* disable test for cpu, gpu, gpuh

* add static string s_manifest = ;

* using NGRAPH_TEST so test can be disable for specific backend

* float number

* revert last change

* default

* support more data type

* change License text

* change License text

* add and ring send recv test

* add and ring send recv test

* skip send_recv_ring

* fix bug

* Run fused op decomposition recursively until no more fused ops.

* Update callback member name.

* Remove redundant conditions.

* Style apply.

fix license header again

MLIR Integration into CPU backend

* [ONNX] Add eyelike operator

* Use shifted square identity in square identity

* Make new helper function to map onnx_types<->ngraph_types

* Add fp16 support to ngraph Python API

* Move helper common.hpp => common.cpp

* Add checker for attribute presence

* Style check

* Add definition of shifted word

* Change return value of attribute presence !(==) -> !=

* Rename is_attribute_present => has_attribute

* Clean-up headers in eyelike.cpp

* Organize headers in common.*pp

* Minor review fixes

* Style check

* Add test for EyeLike with negative k