Integrated: Merge lworld

[Vicente Romero]

Merge lworld into bworld

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Commit messages:
 - additional changes
 - Merge branch 'lworld' into bworld_merge_lworld
 - 8374633: Bang in signatures should go before the type
 - Remove spurious code
 - 8374545: Drop logic for unchecked nullness conversions
 - remove support for LooselyConsistentValue
 - Remove parametric nullity and nullable marker
 - remove hidden option allowNullRestrictedTypesForValueClassesOnly
 - fixing regression test CheckExamples
 - Fixing nullability regression tests
 - ... and 78 more: https://git.openjdk.org/valhalla/compare/b51d2eb2...d9ba3e8b

The merge commit only contains trivial merges, so no merge-specific webrevs have been generated.

Changes: https://git.openjdk.org/valhalla/pull/1864/files
  Stats: 4930 lines in 79 files changed: 4823 ins; 6 del; 101 mod
  Patch: https://git.openjdk.org/valhalla/pull/1864.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1864/head:pull/1864

PR: https://git.openjdk.org/valhalla/pull/1864