RFR: [type-classes] 8377195: Add prototype complex type using polar coordinates [v2]

[Joe Darcy]

> Adding a second flavor of complex numbers with bi-directional conversions.
> 
> Also included Numerical witnesses on both flavors of complex.
> 
> For now, removing the deprecation annotations to make use in jshell less verbose.

Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:

  Doc cleanup.

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Changes:
  - all: https://git.openjdk.org/valhalla/pull/2046/files
  - new: https://git.openjdk.org/valhalla/pull/2046/files/b5e67460..10766f2b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=2046&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=2046&range=00-01

  Stats: 5 lines in 1 file changed: 1 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/valhalla/pull/2046.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2046/head:pull/2046

PR: https://git.openjdk.org/valhalla/pull/2046