RFR: 7903579: JOL: Heap dump parser handles superclasses incorrectly [v2]

[Aleksey Shipilev]

> Current heap dump parser relies on class records to appear after the superclass records appear. This does not actually hold for hprof: we can emit the subclass records first, and only then emit the superclass records.
> 
> Therefore, current heap dump reader is broken when it encounters hierarchical classes. If the superclass was not seen before current class is being parsed, the heap dump reader would silently treat the current class as having _no super klasses_ at all. It would then underestimate the class footprint, because it does not record superclasses.

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Fix up more super klass metadata

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Changes:
  - all: https://git.openjdk.org/jol/pull/53/files
  - new: https://git.openjdk.org/jol/pull/53/files/b721c6e1..7e4a4872

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jol&pr=53&range=01
 - incr: https://webrevs.openjdk.org/?repo=jol&pr=53&range=00-01

  Stats: 24 lines in 2 files changed: 10 ins; 11 del; 3 mod
  Patch: https://git.openjdk.org/jol/pull/53.diff
  Fetch: git fetch https://git.openjdk.org/jol.git pull/53/head:pull/53

PR: https://git.openjdk.org/jol/pull/53