RFR: 8301136: Improve unlink() and unlink_all() of ResourceHashtableBase [v5]

[Xin Liu]

> 1. Apply the same idea of JDK-8300184 to unlink().
> 2. Because ResourceHashtableBase doesn't support copy assignment, client of it has to purge all elements first when it needs to assign it. We would like provide a specialized version called 'unlink_all()'.  We don't need to update each node's _next in this case. We only nullify all buckets. 
> 3. This patch also provides a specialized version of unlink_all() for destructor. We don't even update buckets. it's dead anyway.

Xin Liu has updated the pull request incrementally with one additional commit since the last revision:

  Add lambda API unlink(Function f) per reviewers' request.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12213/files
  - new: https://git.openjdk.org/jdk/pull/12213/files/0e003bab..086750e4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12213&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12213&range=03-04

  Stats: 56 lines in 2 files changed: 55 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12213.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12213/head:pull/12213

PR: https://git.openjdk.org/jdk/pull/12213