RFR: JDK-8304820: Statically allocate ObjectSynchronizer mutexes [v3]

[Justin King]

> Similar to https://git.openjdk.org/jdk/pull/13143, statically allocate mutexes which live for the lifetime of the process.

Justin King has updated the pull request incrementally with one additional commit since the last revision:

  Update approach to avoid implicit constructors
  
  Signed-off-by: Justin King <jcking at google.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13160/files
  - new: https://git.openjdk.org/jdk/pull/13160/files/d6afef79..7aab9bea

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13160&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13160&range=01-02

  Stats: 19 lines in 1 file changed: 11 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/13160.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13160/head:pull/13160

PR: https://git.openjdk.org/jdk/pull/13160