Integrated: 8373953: [bworld] Undo inference changes lub and glb

[Vicente Romero]

remove special support for non-nullable types in lub and gbl

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Commit messages:
 - 8373953: [bworld] Undo inference changes lub and glb

Changes: https://git.openjdk.org/valhalla/pull/1822/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1822&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373953
  Stats: 15 lines in 1 file changed: 0 ins; 9 del; 6 mod
  Patch: https://git.openjdk.org/valhalla/pull/1822.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1822/head:pull/1822

PR: https://git.openjdk.org/valhalla/pull/1822