* separate part of ERC721Mintable into ERC721MetadataMintable
* remove mint and burn from 721 tests
* Fixed linter error.
* fix ERC721 mint tests
* Minor fixes.
(cherry picked from commit 744f567f40)
* separate part of ERC721Mintable into ERC721MetadataMintable
* remove mint and burn from 721 tests
* Fixed linter error.
* fix ERC721 mint tests
* Minor fixes.
(cherry picked from commit 744f567f40)