G-API: Introduce new approach to write accuracy tests (#14757)

* G-API: Introduce new common accuracy test fixture

* Enable Range<> to Seq<> implicit conversion

* Fix shadowing parameters

* Update license headers

* Rename ALIGNED_TYPE to SAME_TYPE

* Move MkRange to tests

* Fix TODO(agolubev) in test instantiations

* Squash simple fixture declarations in one line

* Remove unused line

* Fix Windows issues with macro expansion

* Choose between 1 or 2 matrix initialization

* Redesign common class behavior

Use "views" for GetParam() provided by GTest
base class instead of doing segregation
(with copy!) of common and specific parameters:
request common or specific parameter directly
by index from GetParam()-returned parameters

* Refine user-level API and usage of new test model

* Fix -fpermissive errors

* Remove unnecessary init calls

* Replace GCompileArgs member variable with func ptr

* Rename initMatsRandN to make its behavior explicit

Rename initMatsRandN to initMatrixRandN to eliminate confusion:
initMatsRandN only initialized first matrix (similarly to
initMatrixRandU)

* Fix common of initNothing

* Update copyright dates in missed files

* Add check for specific parameters

* Fix coment stlye

* dnn: fix BNLLLayer implementation

details: https://github.com/BVLC/caffe/blame/1.0/src/caffe/layers/bnll_layer.cpp#L17

* dnn: enable OCV/OpenCL BNLL layer

Keep a local copy of `features` from `flann::GenericIndex ` constructor (#14898)

* Fix warnings on Windows

* Fix #4376

Old flag resulted in software implementation being selected when the Intel decoder is not the primary adapter.

- ReadProtoFromTextFile
- ReadProtoFromTextBuffer

G-API: Implement line and circle draw operations (#14820)

* Implement line and circle draw operations

* Fix comments to review

* tensorflow support mirror pad

* revert macro define

* revert macro define

* reduce code duplication

* revert macro define

requires CMake 3.14+

* Support Eltwise3d

* Refactoring

* Fix test