[lworld] RFR: 8281116: [lworld] Adding Preload attribute support

[Frederic Parain]

Please review this changeset adding support for the Preload attribute.
It includes a logging feature to track and diagnose those optimistic class loading.

Tested with Mach5 tier1.

Thank you,

Fred

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Commit messages:
 - Fix Tabs
 - Adding support for the Preload attribute

Changes: https://git.openjdk.java.net/valhalla/pull/623/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=623&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281116
  Stats: 376 lines in 10 files changed: 372 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/623.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/623/head:pull/623

PR: https://git.openjdk.java.net/valhalla/pull/623