[lworld] RFR: 8294797: [lworld] update javadoc to remove references to primitive classes

[Mandy Chung]

This reverts the javadoc changes for primitive classes and a couple leftover changes due to the previous design that is no longer applicable.

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Commit messages:
 - 8294797: [lworld] update javadoc to remove references to primitive classes

Changes: https://git.openjdk.org/valhalla/pull/774/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=774&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294797
  Stats: 81 lines in 13 files changed: 13 ins; 38 del; 30 mod
  Patch: https://git.openjdk.org/valhalla/pull/774.diff
  Fetch: git fetch https://git.openjdk.org/valhalla pull/774/head:pull/774

PR: https://git.openjdk.org/valhalla/pull/774