Some incremental inlining fixes

[Roland Westrelin]

Hi Tobias,

Thanks for looking at this.

> The comment in SafePointNode::Ideal is a bit misleading because "a
> valid object input" could also mean that the ValueTypeNode has an
> object *field* input.
>
> Maybe change it to:
> 1147     // An allocated ValueTypeNode in the debug info?
> 1148     // Reference the oop directly. Helps removal of useless value
> 1149     // type allocations with incremental inlining.

Right. But allocated ValueTypeNode sounds a bit strange. "A
ValueTypeNode that was already heap allocated"?

Roland.