RFR: 8366038: Thread::SpinRelease should use Atomic::release_store [v2]

[Anton Artemov]

> Hi, please consider the following changes:
> 
> `Thread::SpinRelease()` uses an `OrderAccess::fence()` to prevent loads and stores from within the critical section to float down out of the section. A full fence is expensive and it is an overkill on most platforms. Instead, one can achieve the same effect with `Atomic::release_store()`. 
> 
> Tested in tiers 1 - 3.

Anton Artemov has updated the pull request incrementally with two additional commits since the last revision:

 - Update src/hotspot/share/runtime/thread.cpp
   
   8366038: Updated comments.
   
   Co-authored-by: David Holmes <62092539+dholmes-ora at users.noreply.github.com>
 - Update src/hotspot/share/runtime/thread.cpp
   
   8366038: Updated comments.
   
   Co-authored-by: David Holmes <62092539+dholmes-ora at users.noreply.github.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27035/files
  - new: https://git.openjdk.org/jdk/pull/27035/files/d72316fc..b6daa432

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27035&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27035&range=00-01

  Stats: 5 lines in 1 file changed: 0 ins; 3 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/27035.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27035/head:pull/27035

PR: https://git.openjdk.org/jdk/pull/27035