RFR(XS): 8197931: Null pointer dereference in Unique_Node_List::push of node.hpp:1510

[Roland Westrelin]

Hi Per,

> It seems this patch only adds a number of asserts, so I'm curious as to 
> how this avoids the NULL pointer issue? Am I missing something here?

There's no NULL pointer issue. The asserts were added to appease a static
code analysis tool (parfait).

Roland.