Integrated: Merge lworld

[Vicente Romero]

Merge branch 'lworld' into lw5_merge_lworld
# Conflicts:
#	src/jdk.compiler/share/classes/com/sun/tools/javac/code/Preview.java
#	src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
#	src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java
#	src/jdk.compiler/share/classes/com/sun/tools/javac/util/Names.java

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Commit messages:
 - Merge branch 'lworld' into lw5_merge_lworld
 - Merge lworld
 - Merge lworld
 - 8347754: [lw5] fix the order of nullness markers in signatures
 - Merge lworld
 - Merge lworld
 - Merge lworld
 - Merge lworld
 - Merge lworld
 - 8340125: [lw5] null checks are not being generated for method invocations and array writes
 - ... and 58 more: https://git.openjdk.org/valhalla/compare/94cca4b7...608ad7f1

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

Changes: https://git.openjdk.org/valhalla/pull/1553/files
  Stats: 6801 lines in 101 files changed: 6675 ins; 5 del; 121 mod
  Patch: https://git.openjdk.org/valhalla/pull/1553.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1553/head:pull/1553

PR: https://git.openjdk.org/valhalla/pull/1553