39bab48dee
Don't assume that m_findIter is always valid initially, i.e. after FindFirst() is called, as this is not the case if the memory FS is empty, i.e. which no files had been added to it yet. This also allows to simplify the iteration logic, as we don't need to check m_findArgument (which, in turn, obviates the need to clear it when we reach the end of the iteration) and can just use m_findIter directly. Closes #18416.