#fix FileItem.CreateIntermediateTextFile now creates the text file in UTF-8 if the contents string contains non-ASCII characters.
#change ResponseFile.Create now calls FileItem.CreateIntermediateTextFile.
This fix was made in relation to TTP# 334906, even though that problem was not fixed in the end.
#codereview robert.manuszewski
[CL 2075498 by Steve Robb in Main branch]