RFR: 7903583: JOL: Heap dump parser misses superclasses with empty fields [v2]

[Aleksey Shipilev]

> [CODETOOLS-7903579](https://bugs.openjdk.org/browse/CODETOOLS-7903579) was not complete for old layouter. There are still problems when superclasses do not have fields.

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

  Also fix test

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Changes:
  - all: https://git.openjdk.org/jol/pull/54/files
  - new: https://git.openjdk.org/jol/pull/54/files/3f7a88fc..5b7657a3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jol&pr=54&range=01
 - incr: https://webrevs.openjdk.org/?repo=jol&pr=54&range=00-01

  Stats: 16 lines in 1 file changed: 2 ins; 0 del; 14 mod
  Patch: https://git.openjdk.org/jol/pull/54.diff
  Fetch: git fetch https://git.openjdk.org/jol.git pull/54/head:pull/54

PR: https://git.openjdk.org/jol/pull/54