RFR: 8338529: Initial iteration of numerics modeling interfaces [v3]

[Joe Darcy]

> A refinement of some earlier ideas on the numerics modeling interfaces to inform further discussions.
> 
> This is a "lumpy" rather than "splitty" design in terms of favoring a smaller number of interfaces with more functionality rather than a larger number of interfaces making smaller distinctions.
> 
> Various design comments and to-do's noted in the code.

Joe Darcy has updated the pull request incrementally with two additional commits since the last revision:

 - Add default methods.
 - Respond to review feedback; add default methods.

-------------

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1917/files
  - new: https://git.openjdk.org/valhalla/pull/1917/files/9a508b04..1a1713ec

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1917&range=02
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1917&range=01-02

  Stats: 93 lines in 2 files changed: 76 ins; 0 del; 17 mod
  Patch: https://git.openjdk.org/valhalla/pull/1917.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1917/head:pull/1917

PR: https://git.openjdk.org/valhalla/pull/1917