RFR: 8241390: 'Deadlock' with VM_RedefineClasses::lock_classes() [v2]

[Daniil Titov]

> The change fixes a 'deadlock' situation in VM_RedefineClasses::lock_classes() when the current thread is in the middle
> of redefining the same class. The change is based on the fix [1] suggested in the Jira issue [2] comment.
> [1] http://cr.openjdk.java.net/~jiangli/8241390/webrev.00/
> [2] https://bugs.openjdk.java.net/browse/JDK-8241390
> 
> Testing: :jdk_instrument, tier1-tier3, and tier5 tests pass.

Daniil Titov has updated the pull request incrementally with one additional commit since the last revision:

  Changed test to not use shell scripts
  
  Additional changes:
   - Replaced 'cls' identifier with 'redef_classes'
   - Added a comment that the same class can be pushed to the list multiple times.
  
  Testing: tier1-tier3 tests pass.

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/190/files
  - new: https://git.openjdk.java.net/jdk/pull/190/files/6e6b1b81..3502f018

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=190&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=190&range=00-01

  Stats: 275 lines in 6 files changed: 119 ins; 142 del; 14 mod
  Patch: https://git.openjdk.java.net/jdk/pull/190.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/190/head:pull/190

PR: https://git.openjdk.java.net/jdk/pull/190