RFR: 8278031: MultiThreadedRefCounter should not use relaxed atomic decrement

[Markus Grönlund]

Greetings,

please help review this small adjustment to the reference counter memory order.

Tests: jdk_jfr

Thanks to @kimbarrett for bringing this to attention.

Markus

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

Commit messages:
 - 8278031

Changes: https://git.openjdk.java.net/jdk/pull/6699/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6699&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278031
  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6699.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6699/head:pull/6699

PR: https://git.openjdk.java.net/jdk/pull/6699