Integrated: Merge lworld

[Vicente Romero]

Merge lworld into universal-tvars

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Commit messages:
 - Merge branch 'lworld' into universal-tvars_merge_lworld_1
 - fail during inference if primitive classes are bounds during the first overload resolution phase
 - cleaning up overload resolution code
 - 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
 - ... and 6 more: https://git.openjdk.java.net/valhalla/compare/6c863ce4...3f6df0aa

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

Changes: https://git.openjdk.java.net/valhalla/pull/652/files
  Stats: 1182 lines in 29 files changed: 1079 ins; 26 del; 77 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/652.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/652/head:pull/652

PR: https://git.openjdk.java.net/valhalla/pull/652