RFR: 8259707: LDAP channel binding does not work with StartTLS extension

[Alexey Bakhtin]

Please review a small patch to enable LDAP TLS Channel Binding with StartTLS Extension.
Test from the bug report and jtreg javax/naming tests are passed.

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Commit messages:
 - 8259707: LDAP channel binding does not work with StartTLS extension

Changes: https://git.openjdk.java.net/jdk/pull/2085/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2085&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259707
  Stats: 2 lines in 2 files changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2085.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2085/head:pull/2085

PR: https://git.openjdk.java.net/jdk/pull/2085