Add tests for Table.from_objects and Table.expand_column.

[GregoryTravis]

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[radeusgd]

Cool, tests look great!

IMO Database.Table.from_objects is not needed - it will just confuse users - we will have 2 entries in the Component Browser - one for in-memory that works and one for DB that does nothing useful.

We want to keep instance methods in sync for the APIs to be consistent, but static methods are another story - there is no need to align them and it can even be harmful (as here, adding a duplicate entry to CB). So I'd rather remove this stub.