RFR: JDK-8290887 unused private method in TrustManagerFactoryImpl

[Mark Powers]

https://bugs.openjdk.org/browse/JDK-8290887

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

Commit messages:
 - first iteration

Changes: https://git.openjdk.org/jdk/pull/9616/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9616&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290887
  Stats: 26 lines in 1 file changed: 0 ins; 24 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9616.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9616/head:pull/9616

PR: https://git.openjdk.org/jdk/pull/9616