RFR: 8278560: X509KeyManagerImpl::getAliases might return a good key with others

[Weijun Wang]

Perfect match does not always appear at the beginning if there are multiple KeyTypes.

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Commit messages:
 - 8278560: X509KeyManagerImpl::getAliases might return a good key with others

Changes: https://git.openjdk.java.net/jdk/pull/6804/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6804&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278560
  Stats: 103 lines in 2 files changed: 95 ins; 2 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6804.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6804/head:pull/6804

PR: https://git.openjdk.java.net/jdk/pull/6804