RFR: 8290005: com/sun/jndi/ldap/LdapCBPropertiesTest.java failling with NullPointerException [v5]

[Matthew Donovan]

> In this PR, I added methods to the TransportContext class to synchronize access to the handshakeContext field. I also updated locations in the code that rely on the handshakeContext field to not be null to use the synchronized methods.
> 
> Thanks

Matthew Donovan has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:

 - Merge branch 'master' into socket-close-null
 - reverted changes in SSLEngineImpl
 - I missed a method that needed updating
 - Merge branch 'master' into socket-close-null
 - made handshake context lock final
 - using try/finally in terminateHandshakeContext and using local context variable in all places it should be
 - 8290005: com/sun/jndi/ldap/LdapCBPropertiesTest.java failling with NullPointerException

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13742/files
  - new: https://git.openjdk.org/jdk/pull/13742/files/e95cef8e..ba27e19e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13742&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13742&range=03-04

  Stats: 11334 lines in 452 files changed: 6644 ins; 1916 del; 2774 mod
  Patch: https://git.openjdk.org/jdk/pull/13742.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13742/head:pull/13742

PR: https://git.openjdk.org/jdk/pull/13742