Fix/add comments in x86 long codegen.
Fix/add comments in x86 long codegen.

Change-Id: I40826c9468402f621e3890b221b508c96541a4c3

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst