[lworld] RFR: Implement code generation support for value classes

[Srikanth Adayapalam]

Push code code generation tactics and strategies from B3 to B2 classes.

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Commit messages:
 - Implement code generation support for value classes

Changes: https://git.openjdk.java.net/valhalla/pull/604/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=604&range=00
  Stats: 177 lines in 14 files changed: 112 ins; 13 del; 52 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/604.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/604/head:pull/604

PR: https://git.openjdk.java.net/valhalla/pull/604