RFR: 8255867: SignatureScheme JSSE property does not preserve ordering in handshake messages

[Jamil Nimeh]

This fix adjusts the SunJSSE provider's handling of the jdk.tls.[client | server].SignatureSchemes property and its effect on messages that assert the signature_algorithms and signature_algorithms_cert extensions, or supported_signature_algorithms vectors like those used in TLS 1.2 CertificateRequest messages.  With this change, the ordering of the signature algorithms in the property value will be preserved in the ordering as integer identifiers in the messages itself.  Prior to this fix the property algorithms will be asserted, but in the order as shown in the sun.security.ssl.SignatureAlgorithms enumeration.

This does not affect the default ordering of these signature schemes when the property is not given a value.

JBS: https://bugs.openjdk.java.net/browse/JDK-8255867

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

Commit messages:
 - 8255867: SignatureScheme JSSE property does not preserve ordering in handshake messages

Changes: https://git.openjdk.java.net/jdk/pull/2658/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2658&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255867
  Stats: 384 lines in 2 files changed: 380 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2658.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2658/head:pull/2658

PR: https://git.openjdk.java.net/jdk/pull/2658