RFR: 8296401: ConcurrentHashTable::bulk_delete might miss to delete some objects [v3]

[Leo Korinth]

> ConcurrentHashTable::bulk_delete might miss to delete some objects if a bucket has more than 256 entries. Current uses of ConcurrentHashTable are not harmed by this behaviour. 
> 
> I modified gtest:ConcurrentHashTable to detect the problem (first commit), and fixed the problem in the code (second commit).
> 
> Tests passes tier1-3.

Leo Korinth has updated the pull request incrementally with one additional commit since the last revision:

  fix counting bug

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/10983/files
  - new: https://git.openjdk.org/jdk/pull/10983/files/4508c0b8..1292acbf

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10983&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10983&range=01-02

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10983.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10983/head:pull/10983

PR: https://git.openjdk.org/jdk/pull/10983