RFR: JDK-8166596: TLS support for the EdDSA signature algorithm [v4]

[Jamil Nimeh]

> Hello all,
> This change brings in support for certificates with EdDSA keys (both Ed25519 and Ed448) allowing those signature algorithms to be used both on the certificates themselves and used during the handshaking process for messages like CertificateVerify, ServerKeyExchange and so forth.

Jamil Nimeh has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:

 - Merge
 - Update test to account for JDK-8202343 fix
 - Merge
 - Merge
 - Applied code review comments to tests
 - Fix cut/paste error with ECDH-RSA key exchange
 - Merge
 - Initial EdDSA/TLS solution

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1197/files
  - new: https://git.openjdk.java.net/jdk/pull/1197/files/dee70944..58651fc5

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1197&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1197&range=02-03

  Stats: 192313 lines in 1163 files changed: 125674 ins; 47707 del; 18932 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1197.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1197/head:pull/1197

PR: https://git.openjdk.java.net/jdk/pull/1197