RFR: 8280870: Parallel: Simplify CLD roots claim in Full GC cycle

[Stefan Karlsson]

On Fri, 28 Jan 2022 10:18:19 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Simple change around CLD roots claim logic in `MarkFromRootsTask`.
> 
> Test: hotspot_gc

FWIW, an alternative could be to completely remove the CLD *task* claiming and let all workers rely on the *CLD* claiming in CLDToOopClosure/ClassLoaderData::oops_do.

-------------

PR: https://git.openjdk.java.net/jdk/pull/7265