Investigate Windows support for reading xsave area size cpuid in drutil.

- future commit for reading xsave area size in Windows by using CPUID returns me 1088 bytes. I can't find this to be a valid number, unless I'm missing something. I had expected 960, 1024, 1536 or even 1152 (for xsavec). But non of the component offsets seem to support 1088. I'm probably missing something but it should get looked at more closely.