[jdk11u-dev] RFR: 8274736: Concurrent read/close of SSLSockets causes SSLSessions to be invalidated unnecessarily

[Zhengyu Gu]

Backport this patch for parity with Oracle 11.0.15.

The patch applies cleanly, but new test does not build. This is due to a couple of CRs [1][2] that affect the test's super class `SSLSocketTemplate`, are not in jdk11u.

Additional changes to fix the test:
1. Changed member `private volatile int serverPort = 0;` => `protected volatile int serverPort = 0;` in `SSLSocketTemplate`
2. Changed method `private void doServerSide()` => `protected void doServerSide()` in `SSLSocketTemplate`
3. Added member `protected volatile InetAddress serverAddress = null;` to new test, test never change the value.

Test:
- [x] Passed new test.


[1] [JDK-8209362](https://bugs.openjdk.java.net/browse/JDK-8209362)
[2] [JDK-8230435](https://bugs.openjdk.java.net/browse/JDK-8230435)

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

Commit messages:
- Backport 8822d41fdcc2c2d568badd72635dc587d21dbd63

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/711/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=711&range=00
Issue: https://bugs.openjdk.java.net/browse/JDK-8274736
Stats: 435 lines in 3 files changed: 429 ins; 0 del; 6 mod
Patch: https://git.openjdk.java.net/jdk11u-dev/pull/711.diff
Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/711/head:pull/711

PR: https://git.openjdk.java.net/jdk11u-dev/pull/711