RFR: 8238174: migrate ObjectMonitor::_owner field away from C++ volatile semantics [v2]

[Martin Doerr]

On Wed, 18 Nov 2020 02:25:16 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> Drop volatile from the ObjectMonitor::_owner field. Update all naked
>> field loads to use the new owner_raw() accessor or the existing
>> owner_is_DEFLATER_MARKER() accessor.
>> 
>> Testing: Mach5 Tier1,2,3; only unrelated, known test failures.
>
> Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:
> 
>   @dholmes-ora CR - resolve David's comments.

LGTM

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Marked as reviewed by mdoerr (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/1278