revert back MariaDb1027Platform

Since the JSON type is simply an alias to a LONG TEXT we must force
a comment, otherwise things will not work properly.

Also the test for JSON types should work regardless of native JSON
support (DBAL should add a comment to identify the correct type).

Since it was deprecated.

 Closes #2436

[2.0] DDC-312 -  Refactored View support of all platforms a little - Oracle now also supports the retrieval of the sql used to generate a view so that a common datastructure View is a viable option.

[2.0] Fixed PHP Notice in SchemaTest (only variables should be passed by reference...) and a few other cosmetics in various parts.

--no commit message

reverting the reorganization done in 3455-3456 in order to make merging my experimental branch to trunk easier.