This is in line with the change made for other ports in d53c3b6a: since
the default output directory already includes the variant name in it
there's no need to add it to the executable as well.
PR #9012 (b2e8240268) changed the output to
$(BUILD)/$(PROG) but the tests are still looking for $(PROG).
Also remove the now-unnecessary override of $(PROG) in the standard
variant.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
The xmlns attribute is required for older msbuild version (e.g. for
VS2015). Add it where needed, and reorder the attributes so all
files look the same.
