This accidentally came out and should not have.  Thanks to Eric Kohl
for pointing this out to me.

msi/tests: automation: Test Installer::Products before and after InstallProduct, check product is not/is installed.

The recently introduced code had a bug where it passed the wrong
values into apartment_findfromtype to find the main apartment. Since
this is now the only way the function is used, fix this bug by
changing apartment_findfromtype to apartment_findmain, which only
finds the main apartment.