[lworld] RFR: 8288131: [lworld] Implement javac flag -XDenablePrimitiveClasses

[Vicente Romero]

Primitive classes support should be opted in using a compiler option

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Commit messages:
 - removing whitespace
 - Merge branch 'lworld' into JDK-8288131
 - removing whitespace
 - fixing more hotspot tests
 - updating hotspot tests
 - additional regression tests changes
 - updating more primitive classes tests
 - additional test changes
 - Merge branch 'lworld' into JDK-8288131
 - 8288131: [lworld] Implement javac flag -XDenablePrimitiveClasses

Changes: https://git.openjdk.org/valhalla/pull/758/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=758&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8288131
  Stats: 356 lines in 233 files changed: 139 ins; 43 del; 174 mod
  Patch: https://git.openjdk.org/valhalla/pull/758.diff
  Fetch: git fetch https://git.openjdk.org/valhalla pull/758/head:pull/758

PR: https://git.openjdk.org/valhalla/pull/758