Autogen: Fix autogen test separation bugs

When 6ee5c431 is merged, `autogen_test_number`
is put into the wrong scope. The problem is that RunCmake.Autogen_Qt5_X
tests are created only Qt6 prefix is provided. This commit moves it to
the upper scope.

Fix Xcode specific bug where `foreach(exe IN ITEMS Moc Uic Rcc)` should
be removed.