Integrated: 8316561: [lw5] class file attribute NullRestricted shouldn't be generated for arrays

[Vicente Romero]

This PR is fixing a bug, basically for code like:

value class V {
    V[]! va;
    public implicit V();
}

the compiler shouldn't generate a NullRestricted attribute for field `va` in the future we probably issue a warning or a compiler error for this code pattern.

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Commit messages:
 - 8316561: [lw5] class file attribute NullRestricted shouldn't be generated for arrays

Changes: https://git.openjdk.org/valhalla/pull/928/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=928&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316561
  Stats: 12 lines in 2 files changed: 11 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/928.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/928/head:pull/928

PR: https://git.openjdk.org/valhalla/pull/928