[REG2.065a] Issue 12070 - Variant opCall not static

https://d.puremagic.com/issues/show_bug.cgi?id=12070

If both constructor and opCall exist, `Type()` should be handled as literal syntax for default construction.

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This issue has come from the behavior of the language that was not sure whether useful there.

It has been implemented by #72, but as [I was concerned](https://github.com/D-Programming-Language/dmd/pull/72/files#diff-a5ac4cc0bd5eae55ebabfb77cd005182R80), It had not had strong purpose. So I think the issue should be fixed by changing language behavior.