src/poky:bitbake: tests/fetch: add a test for download paths without a proper filename

For example the miniupnpd recipe has a SRC_URI like this:

    http://miniupnp.tuxfamily.org/files/download.php?file=${BP}.tar.gz

In this case the path is /files/download.php, which isn't useful when
the latest_upstream logic bails early if there is no version in the path.

The logic now also checks in the downloadfilename, so add a test that
this works as expected.

(Bitbake rev: fffbf5d5e1c8556cddf0794e0b303bb0106747a0)

Signed-off-by: Ross Burton <ross.burtonarm.com>
Signed-off-by: Richard Purdie <richard.purdielinuxfoundation.org>

Author: rossburton