[lworld+vector] RFR: [lworld+vector] Borrowing MultiFields initial implementation from https://github.com/fparain/valhalla/tree/multifields. [v2]

[Jatin Bhateja]

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

Jatin Bhateja has refreshed the contents of this pull request, and previous commits have been removed. Incremental views are not available.

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Changes:
  - all: https://git.openjdk.org/valhalla/pull/790/files
  - new: https://git.openjdk.org/valhalla/pull/790/files/c3a6108e..9039a70b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=790&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=790&range=00-01

  Stats: 791 lines in 19 files changed: 53 ins; 583 del; 155 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