fix(windows): re-enable signature check

Fixes #9692.

Signature checking was skipped because we missed a ".virtual" to force
nmake to build the test and test_i3633 targets. This opened up a small
cascade of related formatting issues on Makefiles, and the fact that the
test_i3633 (has there ever been a more poorly named project?) Makefile
did not even work.

Refactored significantly, added same tests to Developer Makefile, and
also now verifying the .msi and installer executable.

We can improve this further but I'd like to get this in to avoid further
critical issues with code signing given the current broken signing
configuration.