Update tests to work with later Delphis

[delphidabbler]

Get csdb tests to compile and run with Delphi 10.4 & 11.

[delphidabbler]

Considering changing to DUnitX from DUnit. Reasons:

1. I'm more used to DUnitX now
2. DUnitX is more feature rich
3. I don't have DUnit installed on my newest Delphi.

Downside is that older Delphis may not be able to run the tests.

Proposal is to:

1. Move DUnit tests into DUnit directory & freeze the code. Update read me to note that the tests are frozen & deprecated.
2. Create new DUnitX directory with new DUnitX test project(s).
3. Create tests for new snippets only in DUnitX.
4. Over time, copy / reimplement tests from DUnit to DUnitX, updating the relevant AdvancedTest.URL entries as changes are made.

[delphidabbler]

Get csdb tests to compile and run with Delphi 10.4 & 11.

I no longer have Delphi 10.4 or 11 - just Delphi 12, so that's what I'll have to use.