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

[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.

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Commit messages:
 - 8377195: Add prototype complex type using polar coordinates

Changes: https://git.openjdk.org/valhalla/pull/2046/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=2046&range=00
  Stats: 529 lines in 2 files changed: 520 ins; 3 del; 6 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