RFR: JDK-8316708: Augment WorstCaseTests with more cases [v6]

[Joe Darcy]

> A new paper
> 
>  "Accuracy of Mathematical Functions in Single, Double, Double Extended, and Quadruple Precision"
> by Brian Gladman, Vincenzo Innocente and Paul Zimmermann
> https://members.loria.fr/PZimmermann/papers/accuracy.pdf
> 
> details the inputs with generate the worst-case observed errors in different math library implementations. The FDLIBM-related worst cases should be added to the test suite.

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

  Update atan2 and hypot tests.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/15879/files
  - new: https://git.openjdk.org/jdk/pull/15879/files/bfe31c64..7b8893c2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15879&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15879&range=04-05

  Stats: 26 lines in 2 files changed: 24 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/15879.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15879/head:pull/15879

PR: https://git.openjdk.org/jdk/pull/15879