[lworld+vector] RFR: [lworld+vector] Borrowing MultiFields initial implementation from https://github.com/fparain/valhalla/tree/multifields.

[Jatin Bhateja]

Merging initial Multifields support added by @fparain from his local repository https://github.com/fparain/valhalla/tree/multifields.

Best Regards,
Jatin

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Commit messages:
 - Borrowing MultiFields initial implementation from https://github.com/fparain/valhalla/tree/multifields.

Changes: https://git.openjdk.org/valhalla/pull/790/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=790&range=00
  Stats: 823 lines in 19 files changed: 615 ins; 85 del; 123 mod
  Patch: https://git.openjdk.org/valhalla/pull/790.diff
  Fetch: git fetch https://git.openjdk.org/valhalla pull/790/head:pull/790

PR: https://git.openjdk.org/valhalla/pull/790