RFR: JDK-8281450: Remove unnecessary operator new and delete from ObjectMonitor

[Thomas Stuefe]

Trivial (?) patch to remove ObjectMonitor operator new and delete. Since ObjectMonitor derives from CHeapObj, we don't need those. 

This also solves the problem that the local new overrules the NMT category flag set in CHeapObj (both currently are mtInternal, so the problem is theoretical).

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Commit messages:
 - update copyright
 - remove ObjMon new and delete

Changes: https://git.openjdk.java.net/jdk/pull/7377/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7377&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281450
  Stats: 20 lines in 2 files changed: 0 ins; 18 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7377.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7377/head:pull/7377

PR: https://git.openjdk.java.net/jdk/pull/7377