the stack to the heap to work around a problem on ia64. Now, roughly
16 months and two compiler updates later, it isn't an issue anymore
in the sense that putting a 1M buffer on the stack just works and we
don't actually need to work around anything anymore.
However, since there's no advantage or need to put the buffer on the
stack (again), this change merely removes the XXX comment describing
that there's an explicit reason for the heap allocation. Hence, this
change is a functional no-op.
PR: ia64/38677
4b290df1dd