Save both the normal window geometry and its maximized position instead
of saving just its current position. This fixes restoring geometry of
the maximized windows as previously they were always restored on the
primary monitor, as their original position was lost.
Use the native {Get,Set}WindowPlacement() functions for a MSW-specific
wxTLWGeometry implementation to achieve this.
Closes#16335.
This requires slightly more work, but ensures that we don't leave any
traces of running the tests in the system registry or file system, as we
can just call DeleteAll() on the config object after finishing with it.
It seems better to organize the tests in different files and just
provide a common fixture-like class to reuse functionality.
Also use this as an opportunity to rewrite the tests to use Catch
directly instead of using CppUnit-compatible macros.
Finally, actually build these tests as part of the test suite.
