[lworld] RFR: 8271508: [lworld] disallow primitive classes with super_class of 0

[Harold Seigel]

Please review this small fix for valhalla bug JDK-8271508.  The fix was tested with a new regression test, with JCK lang and VM, mach5 tiers 1-2 on Linux, Mac OS, and WIndows, and mach5 tiers 3-5 on Linux x64.

Thanks, Harold

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Commit messages:
 - 8271508: [lworld] disallow primitive classes with super_class of 0

Changes: https://git.openjdk.java.net/valhalla/pull/513/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=513&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271508
  Stats: 87 lines in 3 files changed: 80 ins; 2 del; 5 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/513.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/513/head:pull/513

PR: https://git.openjdk.java.net/valhalla/pull/513