[msi/tests] Install tests on win9x and NT4

[Paul Vriens]

Hi,

Currently the install test fail/crash on at least win95 and NT4. The main reason 
I found was that pMsiQueryComponentStateA and pMsiSourceListGetInfoA are not 
guarded.

Does it makes sense to guard every instance of these calls and just continue:

if (pMsiSourceListGetInfoA)
{
    call
    test outcome
}

or should we skip the whole subtest when the function is not available.

Guarding each single item requires 28 of these if-statements or is there an 
other alternative? (like creating a function/macro to deal with this)

Just guarding the functions makes the tests not crash but they still fail (that 
is another issue of course).