RFR: 8331682: Slow networks/Impatient clients can potentially send unencrypted TLSv1.3 alerts that won't parse on the server [v4]

[Artur Barashev]

> https://bugs.openjdk.org/browse/JDK-8331682

Artur Barashev has updated the pull request incrementally with one additional commit since the last revision:

  - Switch server to use plaintext after getting the unexpected plaintext alert message during TLSv1.3 handshake
  - Always send user_cancelled alert before close_notify alert during handshake. This is actually a different issue which was discovered during this fix.
  - Update tests accordingly

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21043/files
  - new: https://git.openjdk.org/jdk/pull/21043/files/accbb49d..e8dcda09

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21043&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21043&range=02-03

  Stats: 103 lines in 4 files changed: 65 ins; 26 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/21043.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21043/head:pull/21043

PR: https://git.openjdk.org/jdk/pull/21043