Integrated: Add flag to control use of type restrictions + test fixes

[Frederic Parain]

Add a VM flag to control use of type restrictions + test fixes

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Commit messages:
 - Add flag to control use of type restrictions + test fixes

Changes: https://git.openjdk.java.net/valhalla/pull/373/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=373&range=00
  Stats: 34 lines in 5 files changed: 9 ins; 6 del; 19 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/373.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/373/head:pull/373

PR: https://git.openjdk.java.net/valhalla/pull/373