[jdk11u-dev] RFR: 8260923: Add more tests for SSLSocket input/output shutdown

[Aleksey Shipilev]

Clean backport to match `11.0.13-oracle`.

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

Commit messages:
 - Backport 9bb1863ed719a2a0108ef514ce59ffc5b4febe21

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/92/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=92&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8260923
  Stats: 59 lines in 1 file changed: 36 ins; 13 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/92.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/92/head:pull/92

PR: https://git.openjdk.java.net/jdk11u-dev/pull/92