RFR: 8265933: Move Java monitor related fields from class Thread to JavaThread

[Patricio Chilano Mateo]

Hi,

Please review the following change. Fields in class Thread related to Java object monitors like _current_pending_monitor, _current_pending_monitor_is_from_java, _current_waiting_monitor and _Stalled should be moved to the JavaThread class. Members _OnTrap and _TypeTag were grouped together with _Stalled but are not used so I removed them. It seems they were part of the ObjectMonitor implementation at some point but I couldn't find how they were used.
Tested in mach5 tier1-2.

Thanks,
Patricio

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Commit messages:
 - fix serviceability agent
 - v1

Changes: https://git.openjdk.java.net/jdk/pull/3722/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3722&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265933
  Stats: 89 lines in 4 files changed: 36 ins; 43 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3722.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3722/head:pull/3722

PR: https://git.openjdk.java.net/jdk/pull/3722