RFR: 8234437: Remove CollectedHeap::safe_object_iterate()

[Kim Barrett]

> On Nov 19, 2019, at 6:11 PM, Per Liden <per.liden at oracle.com> wrote:
> 
> With CMS now removed, there is no longer any GC where CollectedHeap::object_iterate() and CollectedHeap::safe_object_iterate() do different things. Hence, we can remove CollectedHeap::safe_object_iterate() and let all uses of it shift over to use CollectedHeap::object_iterate().
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8234437
> Webrev: http://cr.openjdk.java.net/~pliden/8234437/webrev.0
> 
> /Per

Looks good.