RFR: 8334421: assert(!oldbox->is_unbalanced()) failed: this should not be called for unbalanced region [v2]

[Vladimir Kozlov]

> [JDK-8324969](https://bugs.openjdk.org/browse/JDK-8324969) changes was not complete. When Escape Analysis tries to determine if lock can be eliminated it looks only if corresponding object does not escape. I does not take into account if coarsening locks elimination already happened and created unbalanced regions.
> 
> Added check that not-escaped object is not referenced from an unbalanced region before marking or eliminating corresponding locks.
> 
> Dump additional information for coarsened locks when debugging.
> 
> New regression test was added
> 
> Tested tier1-5,stress,xcomp

Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:

  Address comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19870/files
  - new: https://git.openjdk.org/jdk/pull/19870/files/312f59f4..df37f699

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19870&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19870&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/19870.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19870/head:pull/19870

PR: https://git.openjdk.org/jdk/pull/19870