RFR: 8271939: Clean up primitive raw accessors in oopDesc

[Evgeny Astigeevich]

On Thu, 5 Aug 2021 11:20:58 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

> We have some _raw accessors in oop.hpp and related code. Those are leftover from when Shenandoah required primitive barriers and are no longer needed. Their uses can be replaced with the regular accessors.
> 
> Testing:
>  - [x] tier1
>  - [x] tier2
>  - [x] hotspot_gc

LGTM

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

Marked as reviewed by eastig at github.com (no known OpenJDK username).

PR: https://git.openjdk.java.net/jdk/pull/5017