msi: Make MsiInstallProduct conformance test depend on proper UI level processing.

[Misha Koshelev]

> Well, by definition, that's not really a conformance test because it
> doesn't conform to windows.  Did you make the property public and add
> the property to the Property table?
> 
> http://msdn2.microsoft.com/en-us/library/aa370912.aspx
> 

First of all, I added the Property to the Property table, which is, what
I understand from that link (paragraph three I think) all that it takes
to make it public (in fact, what happens when you go from UI to Execute
is that the value of the property seems to be reset back to the value
from the Properties table).

Two things:
1) I am testing the behavior in UI mode to make sure the test works, but
the actual "test" is to test the mode NONE | otherflags, which, before
the bug fix, would result in a UI install, whereas in Windows (all
versions) it would result in an execute-only install. This test breaks
on wine without the patch to fix it, whereas it would execute on all
Windows version without error, thus in this sense it "conforms" to
Windows. The question is whether we are able to detect a failure to
conform.
2) I tried on Win98 and in Win98 it works the same way it does on Wine.

I will play with it some more, but because of these points it seems to
me that it is still a reasonable test (it will succeed on all version of
Windows, on Wine that properly detects UI flags, but fail on wine that
does not detect UI flags; however, in the future, if wine MSI is made
more like Win XP MSI, it would be possible that we will not be able to
detect failure anymore).

Misha