RFR: 8275800: Redefinition leaks MethodData::_extra_data_lock [v3]

[Coleen Phillimore]

> The Mutex destructor isn't called for the MDO lock.  We found this leak with crashes for the patch to print all mutex locks on error, which is now withdrawn.  It was easily reproduced with that patch.  It is not easily reproduced otherwise.
> I tested this change with that patch though and it passes tier1-6,

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Move constant pool release_C_heap_structures to the end.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6105/files
  - new: https://git.openjdk.java.net/jdk/pull/6105/files/22b38b03..4b52907f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6105&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6105&range=01-02

  Stats: 7 lines in 1 file changed: 4 ins; 3 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6105.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6105/head:pull/6105

PR: https://git.openjdk.java.net/jdk/pull/6105