Quit using `shdocvw.dll`(or `ieframe.dll`) in tests

Internet Explorer will be end of support.
https://blogs.windows.com/windowsexperience/2021/05/19/the-future-of-internet-explorer-on-windows-10-is-in-microsoft-edge/

Currently, some tests using IE were skipped, (see https://github.com/enthought/comtypes/issues/267#issuecomment-1029305670 by @dmwyatt, #271, #298)

However, there still remains tests using `shdocvw.dll`(`ieframe.dll`), which provides IE and web browser classes.
This will likely cause us to inadvertently use the IE class.

To be samples for testing, there is no need to use the DLL, and we plan to replace it with something more universal.