[lworld] RFR: 8347292: [lworld] oopDesc->print() is broken

[Frederic Parain]

Fix implementation of oopDesc->print():
  - remove invalid assert
  - fix printing for better readability
  - fix offsets of nested fields
  
More details are available in the CR.

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Commit messages:
 - Fix oopDesc->print()

Changes: https://git.openjdk.org/valhalla/pull/1328/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1328&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347292
  Stats: 30 lines in 4 files changed: 11 ins; 3 del; 16 mod
  Patch: https://git.openjdk.org/valhalla/pull/1328.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1328/head:pull/1328

PR: https://git.openjdk.org/valhalla/pull/1328