RFR: 8266426: ZHeapIteratorOopClosure does not handle native access properly [v2]

[Albert Mingkun Yang]

> Change the inheritance hierarchy of `ZHeapIteratorOopClosure` so that we can know whether we are loading oops from in-heap or outside-heap (only CLD iteration).

Albert Mingkun Yang has updated the pull request incrementally with two additional commits since the last revision:

 - explicit private
 - cld

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3838/files
  - new: https://git.openjdk.java.net/jdk/pull/3838/files/c29dfb08..33cd1d65

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3838&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3838&range=00-01

  Stats: 37 lines in 1 file changed: 31 ins; 3 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3838.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3838/head:pull/3838

PR: https://git.openjdk.java.net/jdk/pull/3838