fix for #1825

fix for #1825 with two new tests.
(for the test wheels I added, I also added the src to `tests/data/src`

the change is to use the `name` and `version` from the wheel file to build the `InstallRequirement` so that it has a non-None `req` attribute.   When `req` is None, the "unnamed requirement" code path (see #1689) is used, which only works for sdists.