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
