[lworld] RFR: 8364034: [lworld] Pre-register boxing classes in class loaders [v5]

[Frederic Parain]

> Add pre-registration of boxing classes when a class loader is registered by the VM.

Frederic Parain has updated the pull request incrementally with one additional commit since the last revision:

  Restore multiple returns

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Changes:
  - all: https://git.openjdk.org/valhalla/pull/1517/files
  - new: https://git.openjdk.org/valhalla/pull/1517/files/797d8e9e..671136d7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1517&range=04
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1517&range=03-04

  Stats: 6 lines in 1 file changed: 1 ins; 2 del; 3 mod
  Patch: https://git.openjdk.org/valhalla/pull/1517.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1517/head:pull/1517

PR: https://git.openjdk.org/valhalla/pull/1517