This PR fixes some of the inconveniences that we had with lit in nGraph
and aligns configuration files with MLIR/LLVM.
In particular:
  - `make install` is not needed to run lit test with the latest
    compiled version of testing tools (ngraph-opt).
  - LD_LIBRARY_PATH doesn't need to be modified.

* [MLIR] Update MLIR/LLVM repos

To have access to unranked memrefs.

* Fix MLIR forward again to fix lit test in MLIR repo

* [ TI ] TensorIterator m_num_iterations fix

* style

* POC of Split ConstantFolding

* Removed unused code

* code styles

* Added constant folding variadic split file

* Added variadic split + UT

* Update VariadicSplit tests

* set output type

* set output type

* [MLIR]Add clang flag and skip bf16 tests for MLIR.

* Address PR feedback.

* First debug version of support ND input

* Added type_prop tests

* Implemented ND support for SpaceToDepth

* Added type_prop tests for SpaceToDepth

* Added fused op tests

* code refactor

* Fixed DepthToSpaceMode::BLOCKS_FIRST

* Code review remarks introduced

* Code review ramarks. Part.2

* Using NODE_VALIDATION_CHECK introduced

* Add fluid layout converter

* remove const

* Fixed bin constant ops

* Added export

* Fixed buffer size

* Fixed code style

* Add upgrade and downgrade pass for GroupConvolutionBackpropData ops

- Add up/downgrade passes for GroupConvolutionBackpropData operators
- Improve decompose operatorion of v0::GroupConvolutionBackpropData to support N-dimensional data
- Add UT for up/downgrade passes.

* Remove unused variable

* Fix tolerance for all_close_f

* Lower tolerance

* use all_close

* - use construct_validate_infer_types() in CumSum ctor

* - remove unused variable
- relax rank check

* Warning

* Make sure examples compile

* Resolve doc build error due to opset versioning and align dynamic tensor doc to cpp example

* Add latest rc

* Remove deprecated API

* Update brief link summary

* Dist example

* update doc for cpp code examples folder

* Fix typo and toc index

* Build config for example, deprecation in dist test

* style

* Sitemap for ngraph.ai doc content

* Add title to sitemap

* resolve docbuild warnings resultant from sitemap link labeling

* Doc tag for 0.27.1

* Update MKLDNN to v1.0.4.

Build MKLDNN-v1 by default.

* Add bf16 support check.

* Modify visibility.

* Helper in Constant to allow casting values to a different type

Simplify logic needed to extract values from a Constant node, when
the expected data type is specified only as integral or floating point.

* Review comment

* Review comment
Co-Authored-By: Tomasz Socha <tomasz.socha@intel.com>

* Style apply

* Change generate_adjoints to take an OutputVector instead of a NodeVector for deltas.

* Cleanup

* Adjoints class convert to use Output<Node>

* More cleanup

* More cleanup

* Post-merge build issues

* Don't push initial bprops multiple times

* Eliminate GOE correctly

* back-compatibility, unit test

* [MLIR] Update MLIR/LLVM repos

* Move MLIR/LLVM repos forward

This includes fix to affine fusion algorithm.

* Fix issues after merge

* Fix lit test

* [MKLDNN] Emit dgemm for 2D DP FP Dot op

Add support for emitting MKLDNN's double precision FP gemm from a 2D double
precision floating point Dot operation.

* Removed unnecessarily duplicated pattern

* Add f64 matmul support to CPU Emitter + unit test

* Add check for DP unsupported bias in cpu_fusion.cpp

* fix layernorm flatten issue

* update ut

* checkout output val

* fix style

* apply tolerance

Update jenkins-trigger.groovy

Moving to gitlab.

* Make sure examples compile

* Resolve doc build error due to opset versioning and align dynamic tensor doc to cpp example

* Add latest rc

* Remove deprecated API

* Update brief link summary

* Dist example

* update doc for cpp code examples folder

* Fix typo and toc index

* Build config for example, deprecation in dist test

* style

* Fix serializer op name

* cleanup

* [ONNX] Added gatherND op to ONNX importer.

* Added tests.

* Removed new line.

* Update onnx_import.in.cpp

* Changed tests.

* add ut to reproduce issue from PR#3931

* disable ut for plaidml