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