Integrated: Merge lworld

[Vicente Romero]

Merge lworld into universal-tvars

# Conflicts:
#	src/jdk.compiler/share/classes/com/sun/tools/javac/code/Flags.java
#	src/jdk.compiler/share/classes/com/sun/tools/javac/code/Source.java
#	src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.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/resources/compiler.properties
#	test/langtools/tools/javac/diags/examples.not-yet.txt

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Commit messages:
 - Merge branch 'lworld' into universal-tvars_merge_lworld
 - some existing regression tests are failing due to universal tvars changes
 - Adding type system regression tests
 - some bug fixing, adding new regression tests
 - Merge lworld
 - Primitive value conversion
 - updating tests
 - Merge lworld
 - Merge lworld
 - universal type variables: initial prototype
 - ... and 3 more: https://git.openjdk.java.net/valhalla/compare/954f5ca4...b249ca68

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

Changes: https://git.openjdk.java.net/valhalla/pull/641/files
  Stats: 1187 lines in 30 files changed: 1081 ins; 26 del; 80 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/641.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/641/head:pull/641

PR: https://git.openjdk.java.net/valhalla/pull/641