[lworld+vector] RFR: 8314980: [lworld+vector] consider scalarization conditions during ciMultiField creation.

[Jatin Bhateja]

Patch adds a new API _ciEnv::is_multifield_scalarized_, to scalarize multifield (ciField[s]) in case target vector cannot accommodate multifield bundle size, else it creates a hierarchical structure ciMultiField and expose entire multifield bundle as one field to C2 compiler.

This cleans up special handling done in C2 compiler, ci field query APIs and object reconstruction handling  at SafePoint.

Please review and share your feedback.

Best Regards,
Jatin

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Commit messages:
 - 8314980: [lworld+vector] consider scalarization conditions during ciMultiField creation.

Changes: https://git.openjdk.org/valhalla/pull/918/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=918&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314980
  Stats: 128 lines in 7 files changed: 25 ins; 70 del; 33 mod
  Patch: https://git.openjdk.org/valhalla/pull/918.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/918/head:pull/918

PR: https://git.openjdk.org/valhalla/pull/918