[lworld] RFR: 8288135: [lworld] Implement HotSpot flag -XX:+EnablePrimitiveClasses

[David Simms]

Runtime component of -XX:+EnablePrimitiveClasses switch

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Commit messages:
 - Be explicit about which features are enabled in testing
 - Missed preload processing
 - Merge branch 'lworld' into 8288135
 - Merge branch 'lworld' into 8288135
 - Merge branch 'lworld' into 8288135
 - Retain the classfile version checks AND enable flag
 - Silently disable the default on setting if Valhalla is disabled
 - 8288135: [lworld] Implement HotSpot flag -XX:+EnablePrimitiveClasses

Changes: https://git.openjdk.org/valhalla/pull/727/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=727&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8288135
  Stats: 1135 lines in 120 files changed: 804 ins; 56 del; 275 mod
  Patch: https://git.openjdk.org/valhalla/pull/727.diff
  Fetch: git fetch https://git.openjdk.org/valhalla pull/727/head:pull/727

PR: https://git.openjdk.org/valhalla/pull/727