HPCC-10733 Set value for logical file attribute 'ActualSize'

The 'ActualSize' is one of logical file attributes which was added
10 years ago. But, its value is never set. It is set by this fix: if the 
file has @compressedSize, set the @compressedSize to be the
'ActualSize'. If not, set @size to be the 'ActualSize'.