RFR: 8277535: Remove redundant Stream.distinct()/sorted() steps

[Andrey Turbanov]

1. Stream.distinct() is redundant before toSet() collector. Duplicates will be collapsed by Collector.
2. Stream.sorted() is redundant before toMap() collector. Keys will be shuffled by Collector (it's a HashMap in current implementation)

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Commit messages:
 - [PATCH] Remove redundant Stream.distinct()/sorted() steps

Changes: https://git.openjdk.java.net/jdk/pull/5714/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5714&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8277535
  Stats: 4 lines in 3 files changed: 0 ins; 4 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5714.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5714/head:pull/5714

PR: https://git.openjdk.java.net/jdk/pull/5714