[jdk11u-dev] RFR: 8211978: Move testlibrary/jdk/testlibrary/SimpleSSLContext.java and testkeys to network testlibrary

[Amos Shi]

- This PR is for  [JDK-8322178](https://bugs.openjdk.org/browse/JDK-8322178)
- This PR is a hot fix of backport [JDK-8211978](https://bugs.openjdk.org/browse/JDK-8211978) 
  - https://github.com/openjdk/jdk11u-dev/pull/2330

Background
- The original ticket [JDK-8211978](https://bugs.openjdk.org/browse/JDK-8211978) changed 122 files
- While in Java 11 code base, we have more files need to be changed
- So this PR is the hot fix for these more files

Testing
- Test on Local laptop succeeded, MacOS M1 CPU

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Commit messages:
 - Backport 4fe2edae5948e95f1940a64a3e9d4379e8362d8c

Changes: https://git.openjdk.org/jdk11u-dev/pull/2399/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2399&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8211978
  Stats: 37 lines in 13 files changed: 0 ins; 1 del; 36 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2399.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2399/head:pull/2399

PR: https://git.openjdk.org/jdk11u-dev/pull/2399